CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment		Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment		Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201409Member
Beginning balance (shares) at Dec. 31, 2017				25,018						7,675
Beginning balance at Dec. 31, 2017	$ 353,396	$ 1,598		$ 250	$ 88,006	$ 374,783	$ 1,598		$ (20,148)	$ (89,495)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	34,944					34,944
Other comprehensive income (loss), net of tax	(22,537)								(22,537)
Stock repurchased (shares)										23
Stock repurchased	(974)									$ (974)
Stock issued under employee plans (shares)				225
Stock issued under employee plans	855			$ 3	852
Stock-based compensation expense	1,619				1,619
Stock issued to directors (shares)				11
Stock issued to directors	374				374
Ending balance (shares) at Dec. 31, 2018				25,254						7,698
Ending balance at Dec. 31, 2018	369,275	$ (183)	[1]	$ 253	90,851	411,325	$ (183)	[1]	(42,685)	$ (90,469)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(70,513)					(70,513)
Other comprehensive income (loss), net of tax	16,706								16,706
Stock repurchased (shares)										7
Stock repurchased	(154)									$ (154)
Stock issued under employee plans (shares)				46
Stock issued under employee plans	448				448
Stock-based compensation expense	2,229				2,229
Stock issued to directors (shares)				28
Stock issued to directors	$ 612				612
Ending balance (shares) at Dec. 31, 2019	25,328			25,328						7,705
Ending balance at Dec. 31, 2019	$ 318,420			$ 253	94,140	340,629			(25,979)	$ (90,623)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(73,725)					(73,725)
Other comprehensive income (loss), net of tax	7,637								7,637
Stock repurchased (shares)										12
Stock repurchased	(269)									$ (269)
Stock issued under employee plans (shares)				164
Stock issued under employee plans	2,144			$ 2	2,142
Stock-based compensation expense	2,785				2,785
Stock issued to directors (shares)				63
Stock issued to directors	$ 704			$ 1	703
Ending balance (shares) at Dec. 31, 2020	25,555			25,555						7,717
Ending balance at Dec. 31, 2020	$ 257,696			$ 256	$ 99,770	$ 266,904			$ (18,342)	$ (90,892)

[1] During the three-month period ended March 31, 2019, the Company recorded an adjustment reducing retained earnings and contract assets by $0.2 million to correct an error in the adoption of ASC 606.