CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY - 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, 2014		5,002,649
Beginning balance at Dec. 31, 2014	$ 135,967	$ 41,688	$ 49,896	$ 53,107	$ (1,667)	$ (7,057)	$ 0
Increase (Decrease) in Shareholders' Equity
Net income	13,898			13,898
Reclassification of certain income tax effects from accumulated other comprehensive loss	0
Other comprehensive income (loss)	(2,132)				(2,132)
Stock-based compensation recognized in earnings	9		9
Dividends declared	(8,967)			(8,967)
Common shares issued for employee stock purchase plan (in shares)		2,335
Common shares issued for employee stock purchase plan	107	$ 20	87
Purchase of treasury stock	(2,603)					(2,603)
Ending balance (in shares) at Dec. 31, 2015		5,004,984
Ending balance at Dec. 31, 2015	136,279	$ 41,708	49,992	58,038	(3,799)	(9,660)	0
Increase (Decrease) in Shareholders' Equity
Net income	12,475			12,475
Reclassification of certain income tax effects from accumulated other comprehensive loss	0
Other comprehensive income (loss)	(1,129)				(1,129)
Stock-based compensation recognized in earnings	19		19
Dividends declared	(8,903)			(8,903)
Common shares issued for employee stock purchase plan (in shares)		2,125
Common shares issued for employee stock purchase plan	82	$ 18	64
Purchase of treasury stock	(574)					(574)
Ending balance (in shares) at Dec. 31, 2016		5,007,109
Ending balance at Dec. 31, 2016	138,249	$ 41,726	50,075	61,610	(4,928)	(10,234)	0
Increase (Decrease) in Shareholders' Equity
Net income	9,773			9,773
Reclassification of certain income tax effects from accumulated other comprehensive loss	0			818	(818)
Other comprehensive income (loss)	772				772
Stock-based compensation recognized in earnings	29		29
Dividends declared	(8,837)			(8,837)
Noncontrolling investment in joint venture	2						2
Common shares issued for employee stock purchase plan (in shares)		2,230
Common shares issued for employee stock purchase plan	87	$ 18	69
Purchase of treasury stock	(1,881)					(1,881)
Ending balance (in shares) at Dec. 31, 2017		5,009,339
Ending balance at Dec. 31, 2017	$ 138,194	$ 41,744	$ 50,173	$ 63,364	$ (4,974)	$ (12,115)	$ 2