CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock Outstanding [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance beginning at Dec. 31, 2018	$ (17,310)		$ 431	$ 142,600	$ (36,305)	$ (103,926)	$ (20,110)
Balance, Shares beginning at Dec. 31, 2018		34,441,232
Stock-based compensation	1,920			1,920
Exercise of stock options	1,038		1	1,037
Exercise of stock options, Shares		153,967
Settlement of restricted stock units			2	(2)
Settlement of restricted stock units, Shares		169,592
Acquisition of treasury stock	(2,588)					(2,588)
Acquisition of treasury stock, Shares		(394,102)
Other comprehensive income (loss), net	28,765						28,765
Net income (loss)	(45,252)				(45,252)
Balance ending at Sep. 30, 2019	(33,427)		434	145,555	(81,557)	(106,514)	8,655
Balance, Shares ending at Sep. 30, 2019		34,370,689
Balance beginning at Jun. 30, 2019	(47,916)		433	144,188	(79,950)	(106,514)	(6,073)
Balance, Shares beginning at Jun. 30, 2019		34,240,181
Stock-based compensation	479			479
Exercise of stock options	889		1	888
Exercise of stock options, Shares		129,409
Settlement of restricted stock units			0	0
Settlement of restricted stock units, Shares		1,099
Other comprehensive income (loss), net	14,728						14,728
Net income (loss)	(1,607)				(1,607)
Balance ending at Sep. 30, 2019	(33,427)		434	145,555	(81,557)	(106,514)	8,655
Balance, Shares ending at Sep. 30, 2019		34,370,689
Balance beginning at Dec. 31, 2019	$ (14,981)		439	152,404	(58,131)	(107,033)	(2,660)
Balance, Shares beginning at Dec. 31, 2019	34,800,312	34,800,312
Stock-based compensation	$ 4,754			4,754
Exercise of stock options	2,690		4	2,686
Exercise of stock options, Shares		375,643
Settlement of restricted stock units			4	(4)
Settlement of restricted stock units, Shares		367,759
Acquisition of treasury stock	(616)					(616)
Acquisition of treasury stock, Shares		(53,994)
Other comprehensive income (loss), net	8,073						8,073
Net income (loss)	278,384				278,384
Balance ending at Sep. 30, 2020	$ 278,304		447	159,840	220,253	(107,649)	5,413
Balance, Shares ending at Sep. 30, 2020	35,489,720	35,489,720
Balance beginning at Jun. 30, 2020	$ 6,175		443	155,591	(52,709)	(107,649)	10,499
Balance, Shares beginning at Jun. 30, 2020		35,143,033
Stock-based compensation	2,226			2,226
Exercise of stock options	2,027		3	2,024
Exercise of stock options, Shares		287,292
Settlement of restricted stock units			1	(1)
Settlement of restricted stock units, Shares		59,395
Other comprehensive income (loss), net	(5,086)						(5,086)
Net income (loss)	272,962				272,962
Balance ending at Sep. 30, 2020	$ 278,304		$ 447	$ 159,840	$ 220,253	$ (107,649)	$ 5,413
Balance, Shares ending at Sep. 30, 2020	35,489,720	35,489,720