Aggregate Fair Value and Notional Amount of Derivative Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Fair Value	$ (10,381)	$ (48,109)
Notional Amount	1,488,922	1,453,000
Derivative Assets
Derivative [Line Items]
Fair Value	7,786	2,972
Notional Amount	859,360	722,000
Derivative Assets | Interest Rate Swaps
Derivative [Line Items]
Fair Value	5,972	739
Notional Amount	268,000	147,000
Derivative Assets | TBAs
Derivative [Line Items]
Fair Value	1,138
Notional Amount	241,000
Derivative Assets | Swaptions
Derivative [Line Items]
Fair Value	595	2,233
Notional Amount	340,000	575,000
Derivative Assets | Loan Purchase Commitments
Derivative [Line Items]
Notional Amount	360
Derivative Assets | Loan forward Sales Commitments
Derivative [Line Items]
Fair Value	81
Notional Amount	10,000
Derivative Liabilities
Derivative [Line Items]
Fair Value	(18,167)	(51,081)
Notional Amount	629,562	731,000
Derivative Liabilities | Interest Rate Swaps
Derivative [Line Items]
Fair Value	(80)	(1,893)
Notional Amount	50,500	357,500
Derivative Liabilities | TBAs
Derivative [Line Items]
Fair Value	(661)
Notional Amount	235,000
Derivative Liabilities | Futures
Derivative [Line Items]
Fair Value	(528)	(607)
Notional Amount	162,000	234,000
Derivative Liabilities | Loan Purchase Commitments
Derivative [Line Items]
Fair Value	(379)
Notional Amount	42,562
Derivative Liabilities | Cash Flow Hedging | Interest Rate Swaps
Derivative [Line Items]
Fair Value	(16,519)	(48,581)
Notional Amount	$ 139,500	$ 139,500