Transfers and Servicing of Financial Assets (Including Mortgage Banking Activity) - Components of Mortgage Banking Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Mortgage Loan Activity [Line Items]
Balance at beginning of period	$ 128,442
Originations and purchases	(317,579)	(536,673)
Sales, net of gains	320,106	634,540
Balance at end of period	131,478
Gains on sales	9,202	18,429
Total mortgage income	10,133	18,931
Mortgage Loans Held for Sale [Member]
Mortgage Loan Activity [Line Items]
Balance at beginning of period	128,442	267,475
Originations and purchases	317,579	536,673
Sales, net of gains	(310,904)	(616,111)
Other	(3,639)
Balance at end of period	131,478	188,037
Mortgage Income [Member]
Mortgage Loan Activity [Line Items]
Fair value changes of derivatives and mortgage for sale, net	823	364
Gains on sales	9,202	18,429
Servicing and other income, net	108	138
Total mortgage income	$ 10,133	$ 18,931