Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2018	$ 409,762	$ 205	$ 211,431	$ (22,370)	$ 221,328	$ (832)
Beginning Balance, Shares at Dec. 31, 2018		20,528,230
Treasury Stock Beginning Balance, Shares at Dec. 31, 2018				(1,258,250)
Impact of adoption of ASU | ASU 2016-02 [Member]	(1)				(1)
Comprehensive income:
Net income	19,400				19,400
Other comprehensive income:
Change in unrealized gains (losses), net of tax	5,992					5,992
Change in deferred tax valuation allowance	(198)					(198)
Comprehensive income	25,194
Common stock issued upon exercise of options	$ 20		20
Common stock issued upon exercise of options, Shares	5,000	5,000
Share-based compensation	$ 249		249
Dividends to shareholders	(4,819)				(4,819)
Ending Balance at Mar. 31, 2019	430,405	$ 205	211,700	$ (22,370)	235,908	4,962
Ending Balance, Shares at Mar. 31, 2019		20,533,230
Treasury Stock Ending Balance, Shares at Mar. 31, 2019				(1,258,250)
Beginning Balance at Dec. 31, 2019	$ 430,215	$ 205	213,004	$ (22,370)	227,165	12,211
Beginning Balance, Shares at Dec. 31, 2019	19,302,583	20,560,833
Treasury Stock Beginning Balance, Shares at Dec. 31, 2019	(1,258,250)			(1,258,250)
Impact of adoption of ASU | ASU 2016-13 [Member]	$ (594)				(594)
Comprehensive income:
Net income	10,800				10,800
Other comprehensive income:
Change in unrealized gains (losses), net of tax	1,484					1,484
Comprehensive income	$ 12,284
Common stock issued upon exercise of options, Shares	0
Common stock issued, Shares		201
Share-based compensation	$ 263		263
Dividends to shareholders	(5,212)				(5,212)
Ending Balance at Mar. 31, 2020	$ 436,956	$ 205	$ 213,267	$ (22,370)	$ 232,159	$ 13,695
Ending Balance, Shares at Mar. 31, 2020	19,302,784	20,561,034
Treasury Stock Ending Balance, Shares at Mar. 31, 2020	(1,258,250)			(1,258,250)