Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common stock	Paid-in Capital	Accumulated Other Comprehensive Earnings (Loss)	Retained Earnings	Deferred Compensation	Treasury Stock at Cost	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2018	$ 674	$ 305,660	$ (14,572)	$ 908,079	$ 8,354	$ (401,353)	$ 806,842
Shares, Outstanding, Beginning Balance at Dec. 31, 2018	44,504,043
Increase (Decrease) in Shareholders' Equity
Net earnings (loss)				65,473			65,473
Other comprehensive earnings (loss), net of tax			29,301				29,301
Deferred compensation					(1,039)	1,039
Share-based compensation	$ 1	2,891					2,892
Share-based compensation (in shares)	50,213
Dividends and dividend equivalents				(9,803)			(9,803)
Stockholders' Equity Attributable to Parent, Ending Balance at Mar. 31, 2019	$ 675	308,551	14,729	963,749	7,315	(400,314)	894,705
Shares, Outstanding, Ending Balance at Mar. 31, 2019	44,554,256
Increase (Decrease) in Shareholders' Equity
Cumulative-effect adjustment from ASU 2016-13			22	1,073			1,095
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2019	$ 678	321,190	52,473	1,014,046	7,980	(400,979)	995,388
Shares, Outstanding, Beginning Balance at Dec. 31, 2019	44,869,015
Increase (Decrease) in Shareholders' Equity
Net earnings (loss)				(61,267)			(61,267)
Other comprehensive earnings (loss), net of tax			(13,031)				(13,031)
Deferred compensation					(1,010)	1,010
Share-based compensation	$ 1	3,862					3,863
Share-based compensation (in shares)	53,641
Dividends and dividend equivalents				(10,343)			(10,343)
Stockholders' Equity Attributable to Parent, Ending Balance at Mar. 31, 2020	$ 679	$ 325,052	$ 39,464	$ 943,509	$ 6,970	$ (399,969)	$ 915,705
Shares, Outstanding, Ending Balance at Mar. 31, 2020	44,922,656