Earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net (loss) income		$ (63,528)	$ 13,092	$ (109,186)	$ 25,516
Weighted average common stock outstanding – basic (in shares)		54,616,221	57,208,273	54,998,171	57,204,602
Stock options using the treasury method (in shares)		0	195,420	0	198,066
Restricted stock (in shares)		0	4,152	0	4,585
Weighted average common stock outstanding – diluted (in shares)		54,616,221	57,407,845	54,998,171	57,407,253
Loss (earnings) per basic share (usd per share)		$ (1.16)	$ 0.23	$ (1.99)	$ 0.45
Loss (earnings) per diluted share (usd per share)		$ (1.16)	$ 0.23	$ (1.99)	$ 0.44
Affiliated entity | AAMC
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incentive management fee, percent of incentive fee payable in common stock	25.00%
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		153,714	0	156,365	0
Restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)		5,688	0	5,482	0