Fair Value Measures - Impairment Charges by Asset Class (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) property	Mar. 31, 2016 USD ($) property
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Properties impaired | property	14	125
Total impairment loss	$ 6,725	$ 160,500
Number of properties disposed of | property	0
Investment in Real Estate Assets, Net [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impairment loss	$ 6,748
Below-Market Lease Liabilities, Net [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total impairment loss	$ (23)