Mortgage Servicing Rights - Components of Mortgage Servicing Rights Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Servicing income:
Income	$ 8,454	$ 4,064	$ 18,170	$ 7,697
Cost of sub-servicer	(1,162)	(288)	(2,391)	(603)
Net servicing income	7,292	3,776	15,779	7,094
Market valuation adjustments	15,675	(5,553)	(3,842)	(8,265)
Market valuation changes in associated derivatives	(21,814)	0	(21,814)	0
MSR provision for repurchases	(323)	0	(217)	0
MSR income (loss)	$ 830	$ (1,777)	$ (10,094)	$ (1,171)