Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Payments Related to Tax Withholding for Share-based Compensation	$ 2,205	$ 4,725	$ 2,584
Proceeds from Stock Options Exercised	$ 246	4,972	858
Useful life of property	40 years
Depreciation expense from operation	$ 113,500	104,300	90,600
Real estate cost capitalized excluding interest cost	17,400	12,700	11,000
Real estate interest cost capitalized incurred	26,800	$ 14,300	11,400
Impairment losses	8,800
Assets held for sale	71,800
Liabilities held for sale	$ 24,349
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate		4.75%
Senior Notes 4.75 Due 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate	4.75%
Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 101,200	$ 90,100	77,500
Non-Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 12,300	14,200	13,100
Minimum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Maximum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	40 years
Maximum | Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Restructuring Charges [Member]
Summary Of Significant Accounting Policies [Line Items]
Gain / (Loss) on disposal of equipment	$ (7,000)
Transaction Integration And Impairment Costs [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment losses		$ 1,600	$ 0