Consolidated Statement Of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statement Of Stockholders' Equity [Abstract]
Issuance of common stock, shares	550,352	151,150	113,223
Issuance of deferred stock units, shares	7,548	47,506	2,767
Special cash dividend, per share	$ 2		$ 1.5
Purchase of treasury stock, shares		33,856	53,879