Stockholders' Equity (Details Textual) (USD $) In Millions, except Share data	12 Months Ended		3 Months Ended	6 Months Ended	9 Months Ended		3 Months Ended	6 Months Ended
	Dec. 31, 2010	Jun. 30, 2011	Jun. 30, 2011 New open market repurchase program [Member]	Jun. 30, 2011 New open market repurchase program [Member]	Jun. 30, 2011 New open market repurchase program [Member]	Sep. 15, 2010 New open market repurchase program [Member]	Jun. 30, 2011 Predecessor open market repurchase program [Member]	Jun. 30, 2011 Predecessor open market repurchase program [Member]	Dec. 09, 2009 Predecessor open market repurchase program [Member]
Stockholders' Equity (Textuals) [Abstract]
Total capital stock, shares authorized		400,000,000
Common stock, shares authorized	300,000,000	300,000,000
Preferred stock, shares authorized	100,000,000	100,000,000
Common stock, par value per share	$ 0.01	$ 0.01
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares outstanding		0
Additional Stockholders' Equity (Textuals) [Abstract]
Maximum Number of shares authorized for repurchase						4,000,000			3,000,000
Maximum amount of shares authorized under repurchase program						$ 100			$ 100
Condition to conclude repurchase program				Earliest of three years from the commencement date, when the maximum number of shares has been repurchased or when the maximum dollar amount has been expended.
Number of shares repurchased and retired	2,964,528		1,763,566	1,763,566	2,214,838		356,000	356,000
Weighted average price of repurchased and retired shares, per share	$ 33.69		$ 28.31	$ 28.31	$ 28.82		$ 34.24	$ 34.24