Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	9.00%
Investment property, net	$ 2,689,276	$ 2,707,565
Cap rate	7.50%
Occupancy rate	92.50%
Price per square foot	28.00
Fair Value Measurements Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment property, net	$ 25,700
Notes payable carrying amount	1,800,000	1,900,000
Impairment of real estate	7,124
Quoted Prices In Active Markets for Identical Items (Level 1) | Fair Value Measurements Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment property, net	0
Significant Other Observable Inputs (Level 2) | Fair Value Measurements Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment property, net	0
Notes payable fair value	1,800,000	$ 1,900,000
Significant Unobservable Inputs (Level 3) | Fair Value Measurements Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment property, net	$ 25,700