CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED BALANCE SHEETS (Parenthetical) [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)	190,767,191	189,466,395
Common stock, shares outstanding (in shares)	188,338,790	187,037,994
Common stock, unvested restricted shares (in shares)	3,453,991	3,552,143
Treasury stock, shares (in shares)	2,428,401	2,428,401