Fair Value - Schedule of Net Gains on Sales of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of Net Gains on Sales of Loans [Line Items]
Realized gains on sales of loans	$ 233,447	$ 171,128	$ 367,314
Change in unrealized gains on loans held for sale	(14,803)	(7,345)	1,412
Capitalized servicing rights	196,963	306,741	214,285
Provision for repurchases	(15,331)	(16,008)	(7,741)
Interest income	41,824	52,227	40,051
Other	574	182	0
Net gains on sales of loans	409,448	453,840	462,172
Interest Rate Lock Commitments [Member]
Components of Net Gains on Sales of Loans [Line Items]
Gains (losses) on derivative instruments	(574)	(9,088)	21,061
Forward Sales Commitments [Member]
Components of Net Gains on Sales of Loans [Line Items]
Gains (losses) on derivative instruments	(12,335)	(19,747)	(156,201)
MBS Purchase Commitments [Member]
Components of Net Gains on Sales of Loans [Line Items]
Gains (losses) on derivative instruments	$ (20,317)	$ (24,250)	$ (18,009)