Indebtedness - Additional Information (Details) $ in Thousands, ft² in Millions		12 Months Ended
	Sep. 11, 2015	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) ft² Property	Jul. 15, 2020 USD ($)	Jan. 29, 2014 USD ($)
Debt Instrument [Line Items]
Loss from Retirement of Debt		$ 0	$ 0	$ (39)
Long-term Debt, Gross		$ 1,602,785
2030 II Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		2.74%
Long-term Debt, Gross		$ 100,000	$ 0
Effective Interest Rate		2.74%	2.74%
2032 Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		2.84%
Long-term Debt, Gross		$ 200,000	$ 0
Effective Interest Rate		2.84%	2.84%
2029 II Private Placement Notes
Debt Instrument [Line Items]
Interest Rate		3.97%
Long-term Debt, Gross		$ 150,000	$ 150,000
Effective Interest Rate		4.23%
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%	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%	3.96%
2015 Unsecured Term Loan (A)
Debt Instrument [Line Items]
Interest Rate		2.89%
Debt Instrument, term	7 years
Long-term Debt, Gross		$ 260,000	$ 260,000
Debt instrument, interest rate terms		LIBOR plus 110 basis points
2020 Unsecured Term Loan (A)
Debt Instrument [Line Items]
Interest Rate		3.79%
Long-term Debt, Gross		$ 200,000	0
Unsecured term loan, face amount					$ 200,000
Debt instrument, interest rate terms		LIBOR plus 150 basis points
Incremental Term Loan Capacity					$ 100,000
Swaps, Average Fixed Interest Rate		2.49%
2014 Unsecured Term Loan
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 0	200,000
Unsecured term loan, face amount						$ 200,000
Mortgage Loans Payable
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense		335	675
Extinguishment of debt, amount		25,448	117,199
Loss from Retirement of Debt				39
Net carrying value of industrial properties collateralized by mortgage loans		226,182
Long-term Debt, Gross		144,214	174,360
Mortgage Loans Payable | Assumed Mortgage
Debt Instrument [Line Items]
Assumed mortgage loan				$ 11,654
Number of industrial properties acquired | Property				3
Gross leasable area (GLA) of industrial properties acquired | ft²				0.2
Interest Rate				4.17%
Debt Instrument, term				30 years
Unsecured Credit Facility
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense		1,049	$ 2,300
Line of Credit Facility, current borrowing capacity		725,000
Line of Credit Facility, additional borrowings capacity		$ 1,000,000
Number of years of extension of the Line of Credit Facility at election		1 year
Line of Credit Facility, interest rate description		LIBOR plus 110 basis points