Rollforward of Financial Instruments Classified in Level Three of Valuation Hierarchy (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Interest rate lock commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Beginning Balance	$ 2,526	$ 4,397
Total Realized/Unrealized (Losses)/Gains Recorded in (Loss)/ Income	4,408	847
Total Realized/Unrealized (Losses)/Gain Recorded in Comprehensive (Loss) Income	0	0
Settlements	0	0
Transfers to/(from) level 3	0	0
Fair Value, Ending Balance	6,934	5,244
Change in Unrealized (Losses)/Gains Related to Instruments Held	6,934	5,244
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Beginning Balance	243,389	227,297
Total Realized/Unrealized (Losses)/Gains Recorded in (Loss)/ Income	(83,155)	(35,092)
Total Realized/Unrealized (Losses)/Gain Recorded in Comprehensive (Loss) Income	0	0
Issuances	31,185	40,217
Settlements	0	0
Transfers to/(from) level 3	0	0
Fair Value, Ending Balance	191,419	232,422
Change in Unrealized (Losses)/Gains Related to Instruments Held	$ (58,546)	$ 8,941