Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Employee Stock Option [Member] Common Stock [Member]	Employee Stock Option [Member] Additional Paid-in Capital [Member]	Employee Stock Option [Member] Retained Earnings [Member]	Employee Stock Option [Member] AOCI Attributable to Parent [Member]	Employee Stock Option [Member]	Stock Appreciation Rights (SARs) [Member] Common Stock [Member]	Stock Appreciation Rights (SARs) [Member] Additional Paid-in Capital [Member]	Stock Appreciation Rights (SARs) [Member] Retained Earnings [Member]	Stock Appreciation Rights (SARs) [Member] AOCI Attributable to Parent [Member]	Stock Appreciation Rights (SARs) [Member]	Restricted Stock [Member] Common Stock [Member]	Restricted Stock [Member] Additional Paid-in Capital [Member]	Restricted Stock [Member] Retained Earnings [Member]	Restricted Stock [Member] AOCI Attributable to Parent [Member]	Restricted Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2014																13,514,566
Balance at Dec. 31, 2014																$ 13	$ 29,501	$ 56,843	$ (5,945)	$ 80,412
Common shares issued upon exercise of options, net (in shares)					50,224											294,659
Common shares issued upon exercise of options, net																$ 1	2,101	(262)		1,840
Restricted shares issued (in shares)																8,326
Restricted shares issued																	282			282
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)																99,914
Share-based compensation expense																	1,079			1,079
Excess tax benefit from exercies of stock options		$ 618			$ 618		$ 225			$ 225
Cash dividends declared																		(4,255)		(4,255)
Net income																		13,066		13,066
(Loss) gain on cash flow hedging activities																			37	37
Pensions, net of taxes																			(614)	(614)
Comprehensive Income:																				$ 12,489
Purchase and retirement of common shares (in shares)																				0
Balance (in shares) at Dec. 31, 2015																13,917,465
Balance at Dec. 31, 2015																$ 14	33,806	65,392	(6,522)	$ 92,690
Common shares issued upon exercise of options, net (in shares)					81,608											251,996				279,766
Common shares issued upon exercise of options, net																$ 1	1,960	(457)		$ 1,504
Restricted shares issued (in shares)																333,190
Restricted shares issued																	4,558			4,558
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)																55,656
Share-based compensation expense																	1,638			1,638
Cash dividends declared																		(4,707)		(4,707)
Net income																		14,638		14,638
(Loss) gain on cash flow hedging activities																			95	95
Pensions, net of taxes																			190	190
Comprehensive Income:																				$ 14,996
Tax withheld on exercise of Stock Appreciation Rights (SARs)							(405)			(405)
Tax benefit from vesting of acquisition related restricted stock												$ 990			$ 990
Purchase and retirement of common shares (in shares)																(45,100)				(45,100)
Purchase and retirement of common shares																	(131)	(583)		$ (714)
Change in currency translation adjustment, net of taxes																			73	$ 73
Balance (in shares) at Dec. 31, 2016																14,513,207				14,513,207
Balance at Dec. 31, 2016																$ 15	42,416	74,283	(6,164)	$ 110,550
Common shares issued upon exercise of options, net (in shares)					144,443											285,745				336,726
Common shares issued upon exercise of options, net																	2,779	(907)		$ 1,872
Restricted shares issued (in shares)																181,399
Restricted shares issued																	2,780			2,780
Common shares issued upon exercise of Stock Appreciation Rights (SARs) (in shares)																101,596
Share-based compensation expense																	1,664			1,664
Cash dividends declared																		(5,269)		(5,269)
Net income																		15,022		15,022
(Loss) gain on cash flow hedging activities																			(111)	(111)
Pensions, net of taxes																			(1,024)	(1,024)
Comprehensive Income:																				$ 13,907
Tax withheld on exercise of Stock Appreciation Rights (SARs)							$ (1,186)			$ (1,186)
Tax benefit from vesting of acquisition related restricted stock												$ 650			$ 650
Purchase and retirement of common shares (in shares)																				0
Change in currency translation adjustment, net of taxes																			20	$ 20
Balance (in shares) at Dec. 31, 2017																15,081,947				15,081,947
Balance at Dec. 31, 2017																$ 15	$ 49,103	$ 83,129	$ (7,279)	$ 124,968