Income Taxes (Tables)

12 Months Ended

Dec. 31, 2011

Income Taxes [Abstract]

Components Of Income Tax Expense

	For the Years Ended December 31,
	2011		2010		2009
Current income tax expense
Federal	$	70,514	$	62,588	$	50,710
State		6,466		5,506		6,209
		76,980		68,094		56,919
Deferred income tax expense
Federal		17,167		24,035		19,803
State		2,154		2,168		2,819
		19,321		26,203		22,622
Income tax expense	$	96,301	$	94,297	$	79,541

Components Of Deferred Tax Assets And Liabilities

	December 31,
	2011			2010
Current deferred tax assets:
Asset reserves and liabilities not yet deductible for tax	$	14,350		$	17,386
Net current deferred tax assets		14,350			17,386
Current deferred tax liabilities:
Other		(2,582	)		(3,254	)
Net total current deferred tax assets	$	11,768		$	14,132
Noncurrent deferred tax assets:
Asset reserves and liabilities not yet deductible for tax	$	21,145		$	19,906
Tax over book basis of certain assets		17,347			19,376
Net operating loss and tax credit carryforwards		9,095			11,432
Other		874			2,178
Total noncurrent deferred tax assets		48,461			52,892
Less valuation allowance		(2,862	)		(3,859	)
Net noncurrent deferred tax assets		45,599			49,033
Noncurrent deferred tax liabilities:
Book over tax basis of certain assets		(182,084	)		(167,271	)
Other		(18	)		(7	)
Total noncurrent deferred tax liabilities		(182,102	)		(167,278	)
Net total noncurrent deferred tax liabilities	$	(136,503	)	$	(118,245	)

Reconciliation Of Income Tax Provision At Statutory Income Tax Rate And Effective Tax Rate

	2011			2010			2009
Statutory federal rate		35.0	%		35.0	%		35.0	%
State taxes, net of federal tax benefit		2.6			2.7			2.9
Permanent differences		0.5			0.7			0.5
Change in valuation allowance		0.1			(0.1	)		(0.2	)
Changes in tax contingencies		(0.1	)		0.0			(2.4	)
Other items, net		(0.9	)		(0.9	)		(1.4	)
		37.2	%		37.4	%		34.4	%

Reconciliation Of The Beginning And Ending Amount Of Unrecognized Tax Benefits, Excluding Interest And Penalties

Unrecognized Benefit January 1, 2010	$	188
Decreases from Prior Period Tax Positions		—
Increases from Current Period Tax Positions		—
Decreases Related to Settlements of Tax Positions		—
Decreases Due to Lapse of Statute of Limitations		(90	)
Unrecognized Benefit December 31, 2010	$	98
Decreases from Prior Period Tax Positions		—
Increases from Current Period Tax Positions		—
Decreases Related to Settlements of Tax Positions		—
Decreases Due to Lapse of Statute of Limitations		(98	)
Unrecognized Benefit December 31, 2011	$	—