Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	184,307,910	182,416,007
Common stock, shares outstanding (in shares)	184,307,910	182,416,007
Operating Partnership
General partners' capital account, units issued (in units)	184,307,910	182,416,007
General partners' capital account, units outstanding (in units)	184,307,910	182,416,007
Limited partners' capital account, units issued (in units)	5,178,291	5,182,784
Limited partners' capital account, units outstanding (in units)	5,178,291	5,182,784