Summary of Significant Accounting Policies (Accounts Receivable, Net) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 70,990	$ 66,726
Reserve for uncollectible amounts	32,300	33,000
Reserve for uncollectible amounts under ASC 842	27,100	27,300
Reserve for uncollectible amounts under ASC 450		5,700
Collectibility of receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserve for uncollectible amounts under ASC 450	5,200
Tenant Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	3,802	4,339
Straight-line rent receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	64,605	59,288
Other receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 2,583	$ 3,099