Earnings per Share - Schedule of Reconciliation of the Numerators and Denominators of the Basic and Diluted Net Income Per Share Computations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share Basic And Diluted [Abstract]
Net income (loss) available to common stockholders	$ 959	$ 9,682	$ 10,791	$ 3,370	$ 110,153	$ 5,399	$ 4,795	$ (6,164)	$ (10,834)	$ (4,064)	$ 2,909	$ (2,333)	$ 24,802	$ 114,183	$ (14,425)
Shares outstanding:
Weighted average shares outstanding	47,105,744	47,193,120	47,071,608	46,933,094	46,670,735	46,516,614	46,516,614	46,494,638					47,033,311	46,550,042	29,901,405
Diluted shares outstanding	47,849,554	47,834,644	47,721,075	47,534,761	47,227,127	46,763,589	46,657,618	46,494,638					47,701,562	47,008,980	29,901,405
Basic net income (loss) per common share													$ 0.53	$ 2.45	$ (0.48)
Diluted net income (loss) per common share	$ 0.02	$ 0.20	$ 0.23	$ 0.07	$ 2.33	$ 0.12	$ 0.10	$ (0.13)					$ 0.52	$ 2.43	$ (0.48)