Schedule III - Real Estate and Accumulated Depreciation Schedule III - Real Estate and Accumulated Depreciation (Summary) (Details) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
SEC Schedule III, Real Estate, Gross, January 1	$ 2,818,365	$ 2,665,903	$ 2,472,854
Payments to Acquire Property, Plant, and Equipment	237,186	147,645	175,793
Change In Accounts Payable, Real Property Additions	1,829	1,689	(1,855)
Additions Through Contingent Liabilities	292	171	0
Additions Through Assumption Of Debt	0	0	18,311
Change in Straight-line Rent Receivable, Investments in Real Estate	38,000	0	0
Payments for Delayed Tax Exempt Exchange	0	3,775	1,250
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Other Deduction	0	(818)	0
Settlement of Contingent Asset Acquisition Liability	0	(750)	0
Settlement Of Mortgage Note By Real Estate Acquisition	14,000	0	0
Additions Through Settlement Of Mortgage Note	14,000	0	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Cost of Investment in Real Estate Sold	0	0	(450)
SEC Schedule III, Real Estate, Gross, December 31	3,074,846	2,818,365	2,665,903
SEC Schedule III, Real Estate Accumulated Depreciation, January 1	451,483	380,202	313,080
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Depreciation Expense	76,816	71,349	67,173
Finance Lease, Right-of-Use Asset, Amortization	60	0	0
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Investment in Real Estate Sold	0	0	(51)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Other Deduction	(13,906)	0	0
SEC Schedule III, Real Estate Accumulated Depreciation, December 31	514,453	451,483	380,202
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation, Other Addition	0	(68)	0
Inventory, Real Estate, Held-for-sale	$ (34,826)	$ 0	$ 0