Segment Reporting - Schedule of Select Financial Information of Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 208,787	$ 187,473	$ 454,072	$ 254,244
Income (loss) before income taxes	(92,615)	(379,584)	(88,229)	(658,475)
Intercompany servicing revenue and fees	91,321	31,936	204,508	(73,826)
Late fees waived as an incentive for borrowers refinancing loans	14,900	17,900	30,500	33,700
Intercompany revenues	25,910	24,585	53,030	54,895
Operating Segments | Servicing
Segment Reporting Information [Line Items]
Total revenues	117,426	72,813	265,206	9,558
Income (loss) before income taxes	(43,986)	(356,026)	(10,819)	(612,347)
Operating Segments | Servicing | Intercompany
Segment Reporting Information [Line Items]
Intercompany servicing revenue and fees	2,400	3,100	5,300	6,200
Late fees waived as an incentive for borrowers refinancing loans	600	1,000	1,600	2,000
Intercompany revenues	3,000	9,500	7,400	21,000
Operating Segments | Originations
Segment Reporting Information [Line Items]
Total revenues	80,520	110,209	161,328	210,486
Income (loss) before income taxes	20,007	45,615	30,842	62,016
Operating Segments | Originations | Intercompany
Segment Reporting Information [Line Items]
Intercompany revenues	100	200	100	900
Operating Segments | Reverse Mortgage
Segment Reporting Information [Line Items]
Total revenues	15,409	16,137	37,902	60,232
Income (loss) before income taxes	(16,500)	(26,944)	(21,799)	(21,917)
Operating Segments | Other
Segment Reporting Information [Line Items]
Total revenues	200	45	710	75
Income (loss) before income taxes	(52,136)	(42,229)	(86,453)	(86,227)
Eliminations
Segment Reporting Information [Line Items]
Total revenues	(4,768)	(11,731)	(11,074)	(26,107)
Income (loss) before income taxes	$ 0	$ 0	$ 0	$ 0