Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Common stock, par value (in dollars per share)	$ 0.01
Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued (in shares)	100,746,988	98,620,333
Common stock, shares outstanding	100,746,988	98,620,333