Debt - Unsecured Revolving Credit Facility (Details) - Revolving Credit Facility	Jan. 23, 2015 USD ($) option	Sep. 30, 2016 USD ($)	Jul. 06, 2016 USD ($)
Secured Revolving and Term Credit Facility
Line of Credit Facility [Line Items]
Write off of deferred debt issuance cost	$ 1,300,000
Unsecured Revolving Credit Facility
Line of Credit Facility [Line Items]
Current borrowing capacity	$ 800,000,000.0		$ 1,100,000,000.0
Maximum borrowing capacity		$ 1,250,000,000.00
Option to extend maturity, number | option	2
Extension period	6 months
Extension fee percent of outstanding commitments under revolving credit facility	0.075%
Maximum leverage ratio	60.00%
Maximum consolidated secured indebtedness to asset value	40.00%
Minimum tangible net worth	$ 745,400,000.0
Tangible net worth. minimum percent of net equity proceeds received	75.00%
Minimum adjusted EBITDA to consolidated fixed charges	1.50
Minimum net operating income to unsecured debt	1.75
Maximum ratio of unsecured debt to unencumbered asset value	60.00%
Maximum consolidated secured recourse debt to asset value	10.00%
Unsecured Revolving Credit Facility | Eurodollar | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%
Unsecured Revolving Credit Facility | Eurodollar | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.60%
Unsecured Revolving Credit Facility | Base Rate | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Unsecured Revolving Credit Facility | Base Rate | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.60%