Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Outstanding [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, beginning at Dec. 31, 2015	$ (62,330)		$ 411	$ 124,618	$ (96,210)	$ (90,918)	$ (231)
Balance, Shares beginning at Dec. 31, 2015		34,568,942
Stock-based compensation	2,966			2,966
Exercise of stock options	1,503		3	1,500
Exercise of stock options, Shares		255,500
Settlement of restricted stock units			1	(1)
Settlement of restricted stock units, Shares		162,812
Other comprehensive income (loss), net	(27,235)						(27,235)
Net income	20,175				20,175
Balance, ending at Sep. 30, 2016	(64,921)		415	129,083	(76,035)	(90,918)	(27,466)
Balance, Shares ending at Sep. 30, 2016		34,987,254
Balance, beginning at Jun. 30, 2016							(43)
Other comprehensive income (loss), net	(27,423)						(27,423)
Net income	29,866
Balance, ending at Sep. 30, 2016	(64,921)		415	129,083	(76,035)	(90,918)	(27,466)
Balance, Shares ending at Sep. 30, 2016		34,987,254
Balance, beginning at Dec. 31, 2016	$ (72,114)		416	130,189	(125,825)	(90,918)	14,024
Balance, Shares beginning at Dec. 31, 2016	35,048,338	35,048,338
Stock-based compensation	$ 1,614			1,614
Exercise of stock options	3,391		5	3,386
Exercise of stock options, Shares		487,873
Settlement of restricted stock units			4	(4)
Settlement of restricted stock units, Shares		397,522
Acquisition of treasury stock	$ (11,401)					(11,401)
Acquisition of treasury stock, Shares	(1,795,444)	(1,795,444)
Other comprehensive income (loss), net	$ (23,901)						(23,901)
Net income	41,283				41,283
Balance, ending at Sep. 30, 2017	$ (61,128)		425	135,185	(84,542)	(102,319)	(9,877)
Balance, Shares ending at Sep. 30, 2017	34,138,289	34,138,289
Balance, beginning at Jun. 30, 2017							(12,334)
Other comprehensive income (loss), net	$ 2,457						2,457
Net income	5,604
Balance, ending at Sep. 30, 2017	$ (61,128)		$ 425	$ 135,185	$ (84,542)	$ (102,319)	$ (9,877)
Balance, Shares ending at Sep. 30, 2017	34,138,289	34,138,289