CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2015	Dec. 31, 2014
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)	400,000,000	400,000,000
Common stock, shares issued (in shares)	190,631,510	189,466,395
Common stock, shares outstanding (in shares)	188,203,109	187,037,994
Treasury stock, shares (in shares)	2,428,401	2,428,401
Unvested Restricted Stock [Member]
Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares outstanding (in shares)	3,702,751	3,552,143