Selected Quarterly Financial Data (unaudited) - Additional information (Details) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) property	Mar. 31, 2017 USD ($) property	Dec. 31, 2016 USD ($) property	Dec. 31, 2017 USD ($) property	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) property
Quarterly Financial Information Disclosure [Abstract]
Gain on sales of real estate assets			$ 16,100	$ 23,400	$ 41,000	$ 39,519	$ 41,038	$ 56,602
Number of properties sold | property			3	6	6	2		2
Impairment charges		$ 5,100
Loss on extinguishment of debt	$ (45,000)					$ 44,985		$ 27,998