Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Cumulative effect of adoption of updated accounting guidance for equity financial instruments at January 1,2018 | Accounting Standards Update 2016-01 [Member]			$ 16,993	$ (16,993)
Balance at Dec. 31, 2017	$ 3,757	$ 123,180	136,474	12,234	$ (24,527)
Equity based compensation		44
Reclassification of certain tax effects from accumulated other comprehensive income at January 1,2018			(2,619)	2,619
Net income			647			$ 647
Additional minimum pension liability, net of tax				21
Unrealized holding gains (losses) arising during period, net of tax				(312)
Reclassification adjustment for (gains) losses included in net income, net of tax				12
Acquisition of treasury stock					(377)
Balance at Mar. 31, 2018	3,757	123,224	151,495	(2,419)	(24,904)	251,153
Balance at Dec. 31, 2018	3,757	123,168	161,195	(6,660)	(25,928)	255,532
Equity based compensation		57
Shares issued under employee benefit plans					2,107
Shares issued under employee benefit plans (value)		(587)
Net income			15,025			15,025
Additional minimum pension liability, net of tax				28
Unrealized holding gains (losses) arising during period, net of tax				6,141
Reclassification adjustment for (gains) losses included in net income, net of tax				(3,271)
Acquisition of treasury stock					(1,380)
Balance at Mar. 31, 2019	$ 3,757	$ 122,638	$ 176,220	$ (3,762)	$ (25,201)	$ 273,652