Consolidated Statements of Shareholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net of employee benefit funded status adjustment	$ (835)	$ (1,426)	$ (709)
Cash dividends per share	$ 0.60	$ 0.52	$ 0.46
Treasury stock, shares re - issued	41	27	28
Capital in excess of par value
Treasury stock, shares re - issued	41	27	28
Reinvested earnings
Cash dividends per share	$ 0.60	$ 0.52	$ 0.46
Accumulated other comprehensive income (loss)
Net of employee benefit funded status adjustment	$ (835)	$ (1,426)	$ (709)
Treasury stock
Treasury stock, shares re - issued	41	27	28