Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Net Income per Share [Abstract]
Net income	$ (3,827)	$ 4,322	$ 5,853	$ 6,162	$ 544	$ 5,144	$ 6,853	$ 7,591	$ 12,510	[1]	$ 20,132	[1]	$ 10,219	[1]
Less: earnings allocated to RSUs									(305)		(450)		(375)
Net income (loss) available to common shareholders									$ 12,205		$ 19,682		$ 9,844
Weighted average number of common shares outstanding									29,260		29,031		28,776
Basic and diluted									$ 0.42		$ 0.68		$ 0.34

[1] *There is no material difference between net income and comprehensive income.