Consolidated Statement Of Changes In 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
Statement of Stockholders' Equity [Abstract]
Dividends (in usd per share)	$ 2.50	$ 2.51	$ 2.45
Underwriting discounts	$ 1,852	$ 0	$ 2,940