Deferred Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs	$ 464,788	$ 468,971
Less: accumulated amortization	(216,807)	(201,371)
Deferred costs, net	$ 247,981	$ 267,600