Income Taxes (Income Tax Expense Reconciliation to Federal Rate) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Statutory federal income tax	$ 79,486	$ 74,655	$ 73,830
Less federal income tax assumed directly by noncontrolling interests	(49,021)	(44,927)	(44,049)
State income taxes, net of federal income tax benefit	3,755	4,048	4,127
Increase in valuation allowances	1,563	222	327
Interest related to unrecognized tax benefits	(83)	(151)	2
Other	141	(56)	110
Income tax expense	$ 35,841	$ 33,791	$ 34,347

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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-Publisher FASB

-Name Accounting Standards Codification

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in the valuation allowance for deferred tax assets in the period.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to noncontrolling interest income or expense that is exempt from income taxes under enacted tax laws.

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the year/accounting period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to all other items not otherwise listed in the existing taxonomy.

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to state and local income tax expense or benefit.

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The sum of the differences between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in all income tax contingencies, whether recorded or adjusted, during the period.

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