Stockholders' Equity (Details) (USD $)	1 Months Ended						3 Months Ended	12 Months Ended
	Feb. 28, 2013	Dec. 31, 2012	Nov. 30, 2012	Oct. 31, 2012	Aug. 31, 2012	Dec. 31, 2011	Sep. 30, 2012	Dec. 31, 2012
Stockholders' Equity (Textual) [Abstract]
Stock repurchase of its outstanding shares		$ 15,000,000				$ 25,000,000
Stock repurchased and retired								100,852
Cost of stock repurchased and retired								2,500,000
Number of unsettled shares out of shares repurchased		0						0
Number of shares repurchased under the program								0
Special cash dividend		$ 1,300,000		$ 88,800,000				$ 90,439,000
Dividends declared per share	$ 0.15			$ 10.00	$ 10.00		$ 10.00	$ 10.15
Quarterly cash dividend per common share			$ 0.15