Fair Value Measurements - Notional Amounts and Fair Values of Derivatives by Product (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands		Dec. 31, 2015		Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivatives asset, notional		$ 323,108	[1]	$ 440,884	[2]
Derivatives asset, fair value		15,609	[1]	12,111	[2]
Derivative liability, notional		3,268,047	[1]	4,611,704	[2]
Derivative liability, fair value		14,162	[1]	3,505	[2]
Commodity contracts | Futures
Derivatives, Fair Value [Line Items]
Derivative liability, notional		2,943,000	[1]	3,835,600	[2]
Derivative liability, fair value		249	[1]	353	[2]
Other contracts | Interest rate lock commitments
Derivatives, Fair Value [Line Items]
Derivatives asset, notional		203,648	[1]	147,521	[2]
Derivatives asset, fair value		9,161	[1]	7,576	[2]
Derivative liability, notional		48,638	[1]	22,269	[2]
Derivative liability, fair value		923	[1]	1,222	[2]
Other contracts | TBAs
Derivatives, Fair Value [Line Items]
Derivatives asset, notional		35,650	[1]	105,185	[2]
Derivatives asset, fair value		4	[1]	1,026	[2]
Derivative liability, notional		24,350	[1]	105,186	[2]
Derivative liability, fair value		5	[1]	1,018	[2]
Other contracts | TBA sale agreements
Derivatives, Fair Value [Line Items]
Derivatives asset, notional		83,810	[1]	188,178	[2]
Derivatives asset, fair value		6,444	[1]	3,509	[2]
Derivative liability, notional	[1]	223,846
Derivative liability, fair value	[1]	11,614
Other contracts | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative liability, notional	[1]	400		400
Derivative liability, fair value	[1]	2		10
Other contracts | Forward start repurchase agreement
Derivatives, Fair Value [Line Items]
Derivative liability, notional	[2]			636,000
Derivative liability, fair value	[2]			0
Other contracts | ARS purchase commitments
Derivatives, Fair Value [Line Items]
Derivative liability, notional		27,813	[1]	12,249	[2]
Derivative liability, fair value		$ 1,369	[1]	$ 902	[2]

[1] See "Derivative Instruments and Hedging Activities" above for description of derivative financial instruments. Such derivative instruments are not subject to master netting agreements, thus the related amounts are not offset.

[2] See "Derivative Instruments and Hedging Activities" above for description of derivative financial instruments. Such derivative instruments are not subject to master netting agreements, thus the related amounts are not offset.