Equity (Narrative) (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Class of Stock [Line Items]
Stock split payable ratio	two-for-one
Cost of repurchased common stock	$ 24,400,000
Stock dividend paid, date	Aug. 31, 2011
Stock dividend payable, date of record	Aug. 24, 2011
Stock repurchase authorization	100,000,000
Common stock, par value	$ 0.01	$ 0.01
Stock repurchase program, value	14,500,000
Stock repurchase program, share	460,600
Additional capital to common stock		$ 763,000
Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program, share	723,274