Common Stock Repurchase (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended	246 Months Ended
	Jan. 21, 2012	Aug. 07, 2012	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jun. 30, 2012	Jan. 21, 2011
Common Stock Repurchase [Abstract]
Share repurchase authorized amount	$ 60,000,000
Number of shares authorized to be repurchased							2,500,000
Number of shares repurchased		226,000	6,000	151,000	1,180,000	3,524,000
Cost of shares repurchased			113,000	3,179,000	23,519,000	60,070,000
Cost of shares repurchased		$ 3,846,000
Remaining authorized repurchase number of shares			1,320,000		1,320,000	1,320,000	556,000
Average price per share			$ 17.97	$ 21.04