Organization and Business - Schedule of Issuance and Sale of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended												12 Months Ended
	Apr. 11, 2016	Jan. 25, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Common shares sold (in shares)	25,875,000	21,275,000
Net proceeds from issuance of common stock	$ 442,600	$ 321,100
2014 ATM Program | ATM Program | Operating Partnership
Class of Stock [Line Items]
Common shares sold (in shares)			0				0	0	1,007,695	247,397	3,576,010	0	0	0		1,255,092	3,576,010
Weighted average price (in dollars per share)							$ 0.00	$ 0.00	$ 16.56	$ 16.96	$ 15.54	$ 0.00	$ 0.00	$ 0.00		$ 16.63	$ 15.54
Net proceeds from issuance of common stock							$ 0	$ 0	$ 16,439	$ 4,139	$ 54,789	$ 0	$ 0	$ 0		$ 20,578	$ 54,789
2016 ATM Program | ATM Program | Operating Partnership
Class of Stock [Line Items]
Common shares sold (in shares)			135,531	0	0	0									135,531
Weighted average price (in dollars per share)			$ 19.09	$ 0.00	$ 0.00	$ 0.00									$ 19.09
Net proceeds from issuance of common stock			$ 2,561	$ 0	$ 0	$ 0									$ 2,561