Fair Value Measurements - Notional Amounts and Fair Values of Derivatives by Product (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivatives asset, Notional	$ 852,366	$ 65,576
Derivatives asset, Fair Value	2,815	716
Derivative liability, notional	5,845,928	5,920,568
Derivative liability, Fair Value	3,884	1,388
Foreign exchange forward contracts | Other Contracts
Derivatives, Fair Value [Line Items]
Derivative liability, notional	400
Derivative liability, Fair Value	5
Future [Member] | Commodity Contracts
Derivatives, Fair Value [Line Items]
Derivative liability, notional	4,981,000	5,844,000	[1]
Derivative liability, Fair Value	942	766	[1]
Other TBA Contracts [Member] | Other Contracts
Derivatives, Fair Value [Line Items]
Derivatives asset, Notional	31,366	39,576
Derivatives asset, Fair Value	1,038	694
Derivative liability, notional	31,366	39,576
Derivative liability, Fair Value	966	592
TBAs | Other Contracts
Derivatives, Fair Value [Line Items]
Derivatives asset, Notional	821,000	26,000
Derivatives asset, Fair Value	1,777	22
Derivative liability, notional	821,000	26,000
Derivative liability, Fair Value	1,749	22
ARS purchase commitments | Other Contracts
Derivatives, Fair Value [Line Items]
Derivative liability, notional	12,162	10,992
Derivative liability, Fair Value	$ 222	$ 8

[1] For both the three and six months ended June 30, 2018, the diluted net income (loss) per share computation does not include the anti-dilutive effect of 4,050 shares of Class A Stock granted under share-based compensation arrangements (1,336,424 shares for both the three and six months ended June 30, 2017).(2)Represents net income from discontinued operations less net income attributable to non-controlling interest, net of tax divided by weighted average number of shares outstanding.