CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Preferred stock, par or stated value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	290,374,408	271,701,397
Common stock, shares outstanding	289,918,978	271,245,967
Treasury stock, shares	455,430	455,430