Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Employee Stock Loans [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2018	$ 455,941	$ 173	$ 379,085	$ 101,326	$ (4,867)	$ (121)	$ (19,655)
Beginning balance, shares at Dec. 31, 2018		15,793,095
Net income (loss)	(4,073)			(4,073)
Other comprehensive income, net of tax effects	2,100				2,100
Stock based compensation	734		734
Common stock issued upon exercise of stock options	112		112
Common stock issued upon exercise of stock options, shares		6,100
Common stock issued under stock-based incentive plan, shares		21,108
Repayment on employee stock loans	34					34
Cumulative effect of change in accounting principle from implementation of ASU 2017-08 | ASU 2017-08 [Member]	(1,385)			(1,385)
Ending balance at Mar. 31, 2019	453,463	$ 173	379,931	95,868	(2,767)	(87)	(19,655)
Ending balance, shares at Mar. 31, 2019		15,820,303
Beginning balance at Dec. 31, 2019	478,060	$ 174	382,731	125,757	(3)	(77)	(30,522)
Beginning balance, shares at Dec. 31, 2019		15,444,434
Net income (loss)	1,258			1,258
Other comprehensive income, net of tax effects	3,772				3,772
Stock based compensation	756		756
Common stock issued upon exercise of stock options	9		9
Common stock issued upon exercise of stock options, shares		400
Common stock issued under stock-based incentive plan, shares		32,849
Common stock issued under employee stock purchase plan	354		354
Common stock issued under employee stock purchase plan, share		16,764
Repayment on employee stock loans	34					34
Treasury stock purchases	$ (6,892)						(6,892)
Treasury stock purchases, shares	(295,461)	(295,461)
Ending balance at Mar. 31, 2020	$ 477,351	$ 174	$ 383,850	$ 127,015	$ 3,769	$ (43)	$ (37,414)
Ending balance, shares at Mar. 31, 2020		15,198,986