Consolidated Statement of Shareholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]
Balances at Dec. 31, 2016					$ (24,400)
Net income	$ 6,990
Other comprehensive income	2,350				2,350
Shares surrendered upon options and restricted stock vesting to cover taxes	(450)
Balances at Mar. 31, 2017					(22,050)
Balances at Dec. 31, 2017	544,020	$ 460	$ 823,850	$ (262,960)	(17,330)
Net income	24,320			24,320
Other comprehensive income	(1,480)				(1,480)
Shares surrendered upon options and restricted stock vesting to cover taxes	(2,300)		(2,300)
Non-cash compensation expense	1,220		1,220
Balances at Mar. 31, 2018	$ 565,780	$ 460	$ 822,770	$ (238,640)	$ (18,810)