Consolidated Statements of Shareholders' Equity (USD $) In Thousands, except Share data	Total USD ($)	Common Shares	Common Stock USD ($)	Additional Paid-in Capital USD ($)	Retained Earnings USD ($)	Accumulated Other Comprehensive Loss USD ($)
Balance at Dec. 31, 2011	$ 220,852		$ 7,063	$ 15,082	$ 227,944	$ (29,237)
Balance (in shares) at Dec. 31, 2011		18,834,940
Net Earnings	41,584		0	0	41,584	0
Other Comprehensive (Loss) Income	(1,096)		0	0	0	(1,096)
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax withholdings (19,664, 9,457 and 46,152 shares)	2,517		94	2,423	0	0
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax witholdings (19,664, 9,457, and 46,152 shares) (in shares)		250,850
Share-Based Compensation	7,310		0	7,310	0	0
Dividends paid ($0.69, $0.72 and $0.78) per Common Share)	(12,817)		0	0	(12,817)	0
Tax Benefit on Stock Plans	2,047		0	2,047	0	0
Purchases of Common Stock	(25,343)		(233)	(4,464)	(20,646)	0
Purchases of Common Stock (in shares)		(621,340)
Balance at Dec. 31, 2012	235,054		6,924	22,398	236,065	(30,333)
Balance (in shares) at Dec. 31, 2012		18,464,450
Net Earnings	40,231		0	0	40,231	0
Other Comprehensive (Loss) Income	5,362		0	0	0	5,362
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax withholdings (19,664, 9,457 and 46,152 shares)	6,722		173	6,549	0	0
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax witholdings (19,664, 9,457, and 46,152 shares) (in shares)		461,192
Share-Based Compensation	6,689		0	6,689	0	0
Dividends paid ($0.69, $0.72 and $0.78) per Common Share)	(13,233)		0	0	(13,233)	0
Tax Benefit on Stock Plans	5,178		0	5,178	0	0
Purchases of Common Stock	(22,157)		(163)	(8,858)	(13,136)	0
Purchases of Common Stock (in shares)		(434,118)
Balance at Dec. 31, 2013	263,846		6,934	31,956	249,927	(24,971)
Balance (in shares) at Dec. 31, 2013	18,491,524	18,491,524
Net Earnings	50,651		0	0	50,651	0
Other Comprehensive (Loss) Income	(13,622)		0	0	0	(13,622)
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax withholdings (19,664, 9,457 and 46,152 shares)	(748)		56	(804)	0	0
Issue Stock for Directors, Employee Benefit and Stock Plans, net of related tax witholdings (19,664, 9,457, and 46,152 shares) (in shares)		148,557
Share-Based Compensation	7,314		0	7,314	0	0
Dividends paid ($0.69, $0.72 and $0.78) per Common Share)	(14,487)		0	0	(14,487)	0
Tax Benefit on Stock Plans	1,793		0	1,793	0	0
Purchases of Common Stock	(14,096)		(84)	(14,012)	0	0
Purchases of Common Stock (in shares)		(225,034)
Balance at Dec. 31, 2014	$ 280,651		$ 6,906	$ 26,247	$ 286,091	$ (38,593)
Balance (in shares) at Dec. 31, 2014	18,415,047	18,415,047