Indebtedness - Additional Information (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 1,388,845
Unsecured Credit Facility
Debt Instrument [Line Items]
Unamortized Debt Issuance Costs		$ 2,927	$ 3,554
Interest Rate	[1]	3.51%
Mortgage Loans Payable
Debt Instrument [Line Items]
Unamortized Debt Issuance Costs		$ 917	1,246
Extinguishment of debt, amount		72,073
Net carrying value of industrial properties collateralized by mortgage loans		336,242
Long-term Debt, Gross		$ 222,274	297,610
2014 Unsecured Term Loan
Debt Instrument [Line Items]
Interest Rate	[1]	3.39%
Long-term Debt, Gross		$ 200,000	200,000
2015 Unsecured Term Loan
Debt Instrument [Line Items]
Interest Rate	[1]	2.89%
Long-term Debt, Gross		$ 260,000	260,000
2028 Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		3.86%
Long-term Debt, Gross		$ 150,000	150,000
Effective Interest Rate		3.86%
2030 Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		3.96%
Long-term Debt, Gross		$ 150,000	$ 150,000
Effective Interest Rate		3.96%

[1] The interest rate at June 30, 2019 also reflects the derivative instruments we entered into to effectively convert the variable rate to a fixed rate. See Note 10.