Activity for Residential First-Lien Mortgage Servicing Rights (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Servicing Assets at Fair Value [Line Items]
Balance at beginning of period					$ 5,315
Additions	16,000				29,000
Balance at End of Period	43,098				43,098
Mortgage Servicing Rights
Servicing Assets at Fair Value [Line Items]
Balance at beginning of period	18,123		1,562		5,315
Additions	16,148		1,029		28,614		2,608
Changes in assumptions	9,506	[1]	(481)	[1]	10,312	[1]	(481)	[1]
Other changes	(679)	[2]	(46)	[2]	(1,143)	[2]	(63)	[2]
Balance at End of Period	$ 43,098		$ 2,064		$ 43,098		$ 2,064

[1] Primarily reflects changes in discount rates and prepayment assumptions due to changes in interest rates.

[2] Reflects the impact of MSR-related cash flows received during the period.