Fair Value Measurement of Assets and Liabilities - Schedule of Gains and Losses from Fair Value Changes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Gains And Losses From Fair Value Changes [Line Items]
Gains (Losses) on Change in Fair Value	$ 645	$ 14,096	$ 1,549	$ 26,954
Trading Losses, Net [Member] | Trading Securities [Member]
Gains And Losses From Fair Value Changes [Line Items]
Gains (Losses) on Change in Fair Value	(34)	(36)	(43)	(66)
Trading Losses, Net [Member] | Junior Subordinated Debentures Issued to Capital Trusts [Member]
Gains And Losses From Fair Value Changes [Line Items]
Gains (Losses) on Change in Fair Value	0	(234)	0	(2,406)
Gains on Sales of Loans, Net [Member] | Loans Held for Sale [Member]
Gains And Losses From Fair Value Changes [Line Items]
Gains (Losses) on Change in Fair Value	$ 679	$ 14,366	$ 1,592	$ 29,426