Stockholders' Equity - Earnings Per Share (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, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Net income	$ 3,026	$ 4,058	$ 3,451	$ 3,444	$ 68,732	$ 4,220	$ 3,376	$ 3,917	$ 13,979	$ 80,246	$ 20,745
Weighted average shares used to compute net income per common share - basic and diluted (shares)									20,586,066	21,471,041	21,644,163
Basic and diluted net income per common share (usd per share)	$ 0.15	$ 0.20	$ 0.17	$ 0.17	$ 3.28	$ 0.20	$ 0.16	$ 0.18	$ 0.68	$ 3.74	$ 0.96