Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 49,222us-gaap_ProfitLoss	$ 64,781us-gaap_ProfitLoss
Other Comprehensive (Loss) Income:
Net unrealized gain on investments, net of taxes	79	57
Realized gain on investments	0	(38)
Net unrealized (loss) gain on derivatives	(1,350)	37
Amortization of loss on derivatives	388	473
Retirement liability adjustment	360	52
Total	(523)	581
Comprehensive Income	48,699	65,362
Comprehensive Income Attributable to Noncontrolling Interests	(1,575)	(1,478)
Comprehensive Income Adjusted for Noncontrolling Interests	$ 47,124us-gaap_ComprehensiveIncomeNetOfTax	$ 63,884us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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