Shareholder's Equity (Narrative) (Details) (USD $)	0 Months Ended	9 Months Ended
	Oct. 20, 2010 M	Sep. 30, 2011 Y Centers	Sep. 30, 2010
Number of shares, options granted		0
Repurchase of common stock, shares		248,100
Repurchase of common stock		$ 6,185,000
Average price per share		$ 25
Stock repurchased program authorized by the board of directors	40,000,000
Period of stock repurchase program, months	18
Repurchase of additional stock		22,802
Additional options granted under stock incentive plan		0
Number of installments in restricted stock granted to outside directors		3
Portion of restricted stock vested outside directors		33.00%
Number of years restricted for trade		5
Options term		10
Number of shares authorized for grant under share incentive plan		2,760,250
Shares available for future grants/issuance under stock incentive plan		1,547,732
Unrecognized compensation cost on non vested awards		$ 7,239,000
Unrecognized compensation cost on non vested awards, weighted average period of recognition		1.1
Share based payment award shares purchased for award		1,023,000	2,347,000
Outside Directors [Member]
Vesting period of remaining shares		2
Employees [Member]
Vesting period of remaining shares		4
Stock Option or Stock Appreciation Rights [Member]
Shares available for future grants/issuance under stock incentive plan		498,059