CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE LOSS	TREASURY STOCK	NON-CONTROLLING INTEREST
Beginning balance (in shares) at Dec. 31, 2018		7,517,547
Beginning balance at Dec. 31, 2018	$ 143,544	$ 41,763	$ 50,737	$ 69,787	$ (6,636)	$ (12,115)	$ 8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,849			12,839			10
Other comprehensive income	4,737				4,737
Stock-based compensation	498		498
Dividends declared	(6,617)			(6,617)
Common shares issued for employee stock purchase plan (in shares)		2,579
Common shares issued for employee stock purchase plan	69	$ 14	55
Stock split fractional shares (in shares)		(2,330)
Stock split fractional shares	(19)
Ending balance (in shares) at Sep. 30, 2019		7,517,796
Ending balance at Sep. 30, 2019	155,061	$ 41,758	51,290	76,009	(1,899)	(12,115)	18
Beginning balance (in shares) at Jun. 30, 2019		7,519,344
Beginning balance at Jun. 30, 2019	151,521	$ 41,773	51,067	73,565	(2,783)	(12,115)	14
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,654			4,650			4
Other comprehensive income	884				884
Stock-based compensation	185		185
Dividends declared	(2,206)			(2,206)
Common shares issued for employee stock purchase plan (in shares)		782
Common shares issued for employee stock purchase plan	42	$ 4	38
Stock split fractional shares (in shares)		(2,330)
Stock split fractional shares	(19)
Ending balance (in shares) at Sep. 30, 2019		7,517,796
Ending balance at Sep. 30, 2019	155,061	$ 41,758	51,290	76,009	(1,899)	(12,115)	18
Beginning balance (in shares) at Dec. 31, 2019		7,520,740
Beginning balance at Dec. 31, 2019	154,982	$ 41,782	51,487	76,583	(2,777)	(12,115)	22
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,318			11,305			13
Other comprehensive income	2,099				2,099
Stock-based compensation	675		675
Dividends declared	(6,761)			(6,761)
Common shares issued for employee stock purchase plan (in shares)		2,888
Common shares issued for employee stock purchase plan	64	$ 16	48
Director Compensation Plan	80	$ 22	58
Director Compensation Plan (in shares)		3,977
Distributions to noncontrolling interest	(28)						(28)
Ending balance (in shares) at Sep. 30, 2020		7,527,605
Ending balance at Sep. 30, 2020	162,429	$ 41,820	52,268	81,127	(678)	(12,115)	7
Beginning balance (in shares) at Jun. 30, 2020		7,522,573
Beginning balance at Jun. 30, 2020	159,608	$ 41,792	51,956	78,910	(965)	(12,115)	30
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,477			4,472			5
Other comprehensive income	287				287
Stock-based compensation	239		239
Dividends declared	(2,255)			(2,255)
Common shares issued for employee stock purchase plan (in shares)		1,055
Common shares issued for employee stock purchase plan	21	$ 6	15
Director Compensation Plan	80	$ 22	58
Director Compensation Plan (in shares)		3,977
Distributions to noncontrolling interest	(28)						(28)
Ending balance (in shares) at Sep. 30, 2020		7,527,605
Ending balance at Sep. 30, 2020	$ 162,429	$ 41,820	$ 52,268	$ 81,127	$ (678)	$ (12,115)	$ 7