Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Valuation Allowance	$ (80,614,000)	$ (109,319,000)	$ (120,438,000)
REIT distribution requirement (as a percent)		90.00%	90.00%
Tax Cuts and Jobs Act of 2017, income tax expense (Benefit)		$ (64,500,000)
Increase (decrease) in net deferred tax liability	$ (44,800,000)	(66,500,000)
Period in which assets disposition subject to built in gains tax	5 years
Net operating loss carryforward related to TRS entities	$ 910,700,000	973,400,000	$ 1,100,000,000
Difference in bases for entity not subject to income taxes	3,800,000,000	4,100,000,000
Unrecognized tax benefits, income tax penalties and interest accrued	0
Taxable Reit Subsidiaries
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	55,100,000	67,100,000	$ 84,700,000
Tax credit carryforward	14,400,000
Interest Expense Limitation due to Tax Cuts and Jobs Act of 2017
Operating Loss Carryforwards [Line Items]
Valuation Allowances And Reserves, Tax Cuts and Jobs Act of 2017	23,200,000	23,300,000
Deferred Tax Assets, Valuation Allowance	$ 23,200,000	$ 23,300,000