Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities, at Fair Value (Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details)

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Assets and Liabilities, at Fair Value (Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts $ 19,354 $ 38,763
Derivative liabilities 15,845 36,454
Commemorative coins, held at lower of cost or market 41 16
Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Inventory 345,490 245,041
Total assets valued at fair value 350,128 278,773
Liability on borrowed metals 6,437 4,352
Product financing arrangement 156,450 59,358
Contingent earn-out consideration 1,325  
Total liabilities, valued at fair value 180,057 100,164
Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Inventory 345,490 245,041
Total assets valued at fair value 350,128 278,773
Liability on borrowed metals 6,437 4,352
Product financing arrangement 156,450 59,358
Contingent earn-out consideration 0  
Total liabilities, valued at fair value 178,732 100,164
Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Inventory 0 0
Total assets valued at fair value 0 0
Liability on borrowed metals 0 0
Product financing arrangement 0 0
Contingent earn-out consideration 0  
Total liabilities, valued at fair value 0 0
Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Inventory 0 0
Total assets valued at fair value 0 0
Liability on borrowed metals 0 0
Product financing arrangement 0 0
Contingent earn-out consideration 1,325  
Total liabilities, valued at fair value 1,325 0
Liability on margin accounts | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 5,475 8,182
Liability on margin accounts | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 5,475 8,182
Liability on margin accounts | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Liability on margin accounts | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Open sale and purchase commitments | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 262 1,919
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 262 1,919
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Future contracts | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 4,532 13,914
Future contracts | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 4,532 13,914
Future contracts | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Future contracts | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Forward contracts | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 5,576 12,439
Forward contracts | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 5,576 12,439
Forward contracts | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Forward contracts | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative liabilities 0 0
Open sale and purchase commitments | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 4,637 32,347
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 4,637 32,347
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 0 0
Open sale and purchase commitments | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 0 0
Forward contracts | Fair Value on a Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 1 1,385
Forward contracts | Fair Value on a Recurring Basis | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 1 1,385
Forward contracts | Fair Value on a Recurring Basis | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts 0 0
Forward contracts | Fair Value on a Recurring Basis | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets - future and forward contracts $ 0 $ 0