Fair Value Measurements - Schedule Fair Value Measurements Inputs (Details) - USD ($)	Mar. 31, 2019	Jan. 31, 2019	Dec. 31, 2018
Unsecured Term Loan [Member] | Unsecured Term Loan, Expiring January 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Face amount of debt instrument	$ 300,000,000	$ 300,000,000
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets			$ 76,000
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements Using Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets			0
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements Using Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets			76,000
Fair Value, Measurements, Recurring [Member] | Fair Value Measurements Using Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap assets			0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired properties held for sale	3,850,000
Impaired real estate assets			35,036,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements Using Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired properties held for sale	0
Impaired real estate assets			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements Using Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired properties held for sale	3,850,000
Impaired real estate assets			0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value Measurements Using Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired properties held for sale	$ 0
Impaired real estate assets			$ 35,036,000