CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	130,066,055	129,117,946
Common stock, shares outstanding (in shares)	127,638,057	126,689,545
Treasury stock, shares (in shares)	2,428,401	2,428,401
Restricted Stock [Member]
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares outstanding (in shares)	3,576,939	3,951,950