Schedule II - Valuation and Qualifying Accounts - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance at beginning of period	[1]	$ 0	$ 20,438	$ 17,066
Charged to expenses	[1]	22,377		9,254
Adjustments to valuation accounts	[1]	0		0
Deductions	[1]	0		(5,882)
Balance at end of period	[1]	22,377	0	20,438
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
Balance at beginning of period		42,703	45,413	54,155
Charged to expenses		0	0	0
Adjustments to valuation accounts		(5,746)	(2,710)	(8,742)
Deductions		0	0	0
Balance at end of period		$ 36,957	$ 42,703	$ 45,413

[1] Includes allowances on accounts receivable and straight-line rents. Effective January 1, 2019, in accordance with the adoption of Topic 842, the Company includes provision for doubtful accounts in Revenues from rental properties, net on the Company's Consolidated Statements of Income. If a lessee's accounts receivable balance is considered uncollectible, these uncollectible lessee lease receivables would be recognized as a reduction in revenues and would not be considered an allowance. With this implementation, the Allowance for Uncollectible Accounts was re-characterized to be appropriately reflected as reductions in revenues for uncollectible amounts. In addition, the Company also recognizes a general reserve which is included for the year ended December 31, 2020. See Footnote 1 of the Notes to the Consolidated Financial Statements for additional disclosure.