Fair Value Disclosures (Estimated Fair Values and Carrying Amounts of Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, carrying value	$ 200,537	$ 223,394	$ 160,865	$ 441,364
Cash and cash equivalents, fair value	200,537	223,394
Restricted cash, current and non-current, carrying value	168,953	188,526
Restricted cash, current and non-current, fair value	168,953	188,526
Long-term debt and other obligations, carrying amount	11,573,326	11,594,500
Long-term debt and other obligations, fair value	$ 11,962,914	$ 11,892,587
Cash and Cash Equivalents [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Level in Fair Value Hierarchy	1
Restricted cash, current and non-current [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Level in Fair Value Hierarchy	1
Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Level in Fair Value Hierarchy	2