Fair Value Disclosures (Estimated Fair Values and Carrying Amounts of Assets and Liabilities) (Details) - USD ($)		Mar. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, carrying value		$ 205,192,000	$ 567,599,000
Cash and cash equivalents, fair value		205,192,000	567,599,000
Restricted cash, current and non-current, carrying value		120,128,000	129,547,000
Restricted cash, current and non-current, fair value		120,128,000	129,547,000
Long-term debt and other obligations, carrying amount	[1]	13,492,973,000	12,171,142,000
Long-term debt and other obligations, fair value		14,005,423,000	$ 12,660,013,000
Cash and Cash Equivalents [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, carrying value		1
Restricted cash, current and non-current, carrying value		1
Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt and other obligations, carrying amount		$ 2

[1] Balances reflect debt issuance costs as a direct reduction from the respective carrying amounts of debt, with the exception of debt issuance costs associated with the Company's revolving credit facilities. See note 2.