Consolidated Statements Of Stockholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common dividends, per share	$ 0.43	$ 0.39	$ 0.36
Stock issued during period, shares, new issues	48,705		19,550
Issuance of shares of common stock under the stock incentive plan - restricted stock and restricted stock units	162	9	45
Issuance of shares of common stock under the stock incentive plan - stock options including income tax benefits	199	155	13
Common Stock [Member]
Stock issued during period, shares, new issues	48,705		19,550
Issuance of shares of common stock under the stock incentive plan - restricted stock and restricted stock units	162	9	45
Issuance of shares of common stock under the stock incentive plan - stock options including income tax benefits	199	155	13
Paid-In Capital [Member]
Stock issued during period, shares, new issues	48,705		19,550
Issuance of shares of common stock under the stock incentive plan - restricted stock and restricted stock units	162	9	45
Issuance of shares of common stock under the stock incentive plan - stock options including income tax benefits	199	155	13
Retained Earnings [Member]
Common dividends, per share	$ 0.43	$ 0.39	$ 0.36