Consolidated Statements of Shareholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Issuance of common stock tax benefits	$ 16	$ 47	$ 681
Cash dividends	$ 0.72	$ 0.72	$ 0.72
Common Stock
Issuance of common stock tax benefits	16	47	681
Additional Paid-in Capital
Issuance of common stock tax benefits	$ 16	$ 47	$ 681
Retained Earnings
Cash dividends	$ 0.72	$ 0.72	$ 0.72