Servicing of Residential Loans - Schedule of Servicing Rights Carried at Fair Value (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	$ 930,333	$ 1,427,331	$ 949,593	$ 1,682,016
Sales	(12,326)	(28,235)	(12,420)	(28,235)
Other	0	(4,733)	0	(4,733)
Change in fair value due to:
Changes in valuation inputs or other assumptions	(34,751)	(127,713)	(52,281)	(386,173)
Other changes in fair value	(31,963)	(59,780)	(67,949)	(127,900)
Total change in fair value	(66,714)	(187,493)	(120,230)	(514,073)
Balance at end of the period	870,758	1,255,351	870,758	1,255,351
Corporate Joint Venture | Sale Of Servicing Rights To WCO
Change in fair value due to:
Servicing Rights Sold, Accounted For As Financing		35,600		35,600
Purchases
Servicing Asset at Fair Value, Amount [Roll Forward]
Additions	73	2,202	519	21,839
Servicing Rights Capitalized Upon Sales of Loans
Servicing Asset at Fair Value, Amount [Roll Forward]
Additions	$ 19,392	$ 46,279	$ 53,296	$ 98,537