Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2015	Dec. 31, 2014
Consolidated Balance Sheets
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	120,000,000	120,000,000
Common stock, shares issued	40,789,138	40,360,069
Common stock, shares outstanding	40,789,138	40,360,069