Earnings Per Share - Components of Basic and Diluted EPS (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
Earnings Per Share [Abstract]
Net income	$ 2,976	$ 2,567	$ 1,873	$ 2,738	$ 3,275	$ 2,943	$ 2,509	$ 3,041	$ 10,154	$ 11,768	$ 13,502
Less: dividends paid to participating securities									0	(18,987)	0
Less: income allocated to participating securities									(12)	0	(12,939)
Net income / (loss) attributable to common stockholders									$ 10,142	$ (7,219)	$ 563
Weighted average common shares outstanding — basic (in shares)									45,716,757	24,108,362	2,276,694
Dilutive effect of stock options and restricted stock units (in shares)									2,158,765	0	1,613,427
Weighted average common shares outstanding — diluted (in shares)									47,875,522	24,108,362	3,890,121
Net income / (loss) per share:
Basic (USD per share)	$ 0.06	$ 0.06	$ 0.04	$ 0.06	$ 0.07	$ 0.06	$ (6.09)	$ 0.06	$ 0.22	$ (0.30)	$ 0.25
Diluted (USD per share)	$ 0.06	$ 0.05	$ 0.04	$ 0.06	$ 0.07	$ 0.06	$ (6.09)	$ 0.04	$ 0.21	$ (0.30)	$ 0.14