Condensed Consolidated Statements of Stockholders' Equity Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other comprehensive Income (Loss) [Member]
Common stock, shares, outstanding		109,682
Total Stockholders' Equity	$ 272,443	$ 1,097	$ 831,271	$ 798,743	$ (1,347,677)	$ (10,991)
Net earnings (loss)	(19,843)			(19,843)
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	1,648					1,648
Exercise of stock options, shares		36
Exercise of stock options	374		374
Vesting of restricted share units, shares		66
Vesting of restricted share units	(1)		(1)
Shares withheld for employee taxes on awards vested & exercised	(195)		(195)
Stock-based compensation	1,862		1,862
Net earnings (loss)	(6,090)
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	(477)
Common stock, shares, outstanding		109,784
Total Stockholders' Equity	254,977	$ 1,097	833,311	777,589	(1,347,677)	(9,343)
ASU adoption adjustment	(1,311)			(1,311)
Net earnings (loss)	13,753			13,753
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	(2,125)					(2,125)
Exercise of stock options, shares		61
Exercise of stock options	597	$ 1	596
Vesting of restricted share units, shares		25
Vesting of restricted share units	0
Stock-based compensation	1,133		1,133
Common stock, shares, outstanding		109,870
Total Stockholders' Equity	268,335	$ 1,098	835,040	791,342	(1,347,677)	(11,468)
Common stock, shares, outstanding		109,910
Total Stockholders' Equity	286,517	$ 1,099	838,436	805,924	(1,347,677)	(11,265)
Net earnings (loss)	7,323	0	0	7,323	0	0
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	521	$ 0	0	0	0	521
Exercise of stock options, shares		284
Exercise of stock options	2,892	$ 3	2,889	0	0	0
Vesting of restricted share units, shares		218
Vesting of restricted share units	0	$ 2	(2)	0	0	0
Shares withheld for employee taxes on awards vested & exercised	(1,734)	0	(1,734)	0	0	0
Stock-based compensation	709	$ 0	709	0	0	0
Net earnings (loss)	101,778			101,778
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	304
Common stock, shares, outstanding		110,412
Total Stockholders' Equity	294,252	$ 1,104	840,298	811,271	(1,347,677)	(10,744)
ASU adoption adjustment	(1,976)	$ 0	0	(1,976)	0	0
Net earnings (loss)	94,455			94,455
Foreign currency translation adjustments, net of tax of $(57) and $(565), and $81 and $(127), for the three and six months ended 2019 and 2018, respectively	(217)					(217)
Exercise of stock options, shares		101
Exercise of stock options	1,418	$ 1	1,417
Vesting of restricted share units, shares		49
Vesting of restricted share units	0
Stock-based compensation	1,982		1,982
Common stock, shares, outstanding		110,562
Total Stockholders' Equity	$ 391,890	$ 1,105	$ 843,697	$ 905,726	$ (1,347,677)	$ (10,961)