Income Taxes (Tax Effects of Temporary Differences and Carryforwards Included in Net Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Examination [Line Items]
Property, primarily differences in depreciation and amortization, the tax basis of land assets and the treatment of interests and certain costs	$ (269,758)	$ (300,395)	$ (409,803)
Operating loss and interest deduction carryforwards	133,243	146,732	195,415
Expense accruals and other	11,910	12,890	18,185
Valuation allowance	(80,614)	(109,319)	(120,438)
Net deferred tax liabilities	(205,219)	(250,092)	(316,641)
Research and Innovation Acquisition
Income Tax Examination [Line Items]
Net deferred tax liabilities	0		(9,446)
Deferred tax assets, net		19,262
217 Miscellaneous Acquisitions
Income Tax Examination [Line Items]
Net deferred tax liabilities	(922)	(4,510)	0
Established Beginning Deferred Tax Assets or Liabilities
Income Tax Examination [Line Items]
Net deferred tax liabilities	$ (922)		$ (9,446)
Deferred tax assets, net		$ 14,752