Indebtedness - Additional Information (Details) $ in Thousands, ft² in Millions		3 Months Ended
		Mar. 31, 2018 USD ($) ft² Property	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Number of industrial properties | Property		485
Gross leasable area (GLA) of industrial properties | ft²		60.1
Loss from Retirement of Debt		$ (39)	$ (1,653)
Unsecured Credit Facility
Debt Instrument [Line Items]
Unamortized Debt Issuance Costs		4,495		$ 4,781
Mortgage Loans Payable
Debt Instrument [Line Items]
Unamortized Debt Issuance Costs		1,644		1,806
Extinguishment of debt, amount		157,782
Loss from Retirement of Debt		39
Net carrying value of industrial properties collateralized by mortgage loans		$ 452,685
2014 Unsecured Term Loan
Debt Instrument [Line Items]
Debt Instrument Interest Rate Change Due to Investment Grade Rating		10 basis point
Interest Rate	[1]	3.39%
2015 Unsecured Term Loan
Debt Instrument [Line Items]
Debt Instrument Interest Rate Change Due to Investment Grade Rating		10 basis point
Interest Rate	[1]	2.89%
Assumed Mortgage | Mortgage Loans Payable
Debt Instrument [Line Items]
Assumed Mortgage Loan		$ 11,654
Number of industrial properties | Property		3
Gross leasable area (GLA) of industrial properties | ft²		0.2
Interest Rate		4.17%
2028 Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		3.86%
Senior Unsecured Notes, Gross		$ 150,000		0
Effective Interest Rate		3.86%
2030 Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		3.96%
Senior Unsecured Notes, Gross		$ 150,000		$ 0
Effective Interest Rate		3.96%

[1] The interest rate at March 31, 2018 also reflects the interest rate protection agreements we entered into to effectively convert the variable rate to a fixed rate. See Note 10.