Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current taxes [Abstract]
Federal	$ (1,271,000)	$ 9,388,000	$ 8,614,000
State	774,000	2,109,000	2,719,000
Foreign	1,754,000	1,707,000	196,000
Deferred taxes [Abstract]
Federal	4,803,000	2,169,000	16,148,000
State	413,000	438,000	1,964,000
Foreign	249,000	(425,000)	804,000
Income tax expense	6,722,000	15,386,000	30,445,000
Deferred tax asset [Abstract]
Accruals and reserves	10,910,000	10,068,000
Deferred compensation	6,597,000	9,754,000
Share-based payments	12,213,000	15,418,000
Net operating loss carryforwards	7,914,000	7,351,000
Other assets and liabilities	1,533,000	1,991,000
Deferred tax assets, Gross	39,167,000	44,582,000
Valuation allowance	(3,242,000)	(2,957,000)
Total	35,925,000	41,625,000
Deferred tax liability [Abstract]
Property and equipment	(47,317,000)	(39,447,000)
Intangible assets	(15,700,000)	(17,998,000)
Other assets and liabilities	(122,000)	(830,000)
Total	(63,139,000)	(58,275,000)
Net deferred tax liability	(27,214,000)	(16,650,000)
Net current deferred tax asset	8,839,000	10,314,000
Net long-term deferred tax liability	(36,053,000)	(26,964,000)
Tax effect on interest rate swap agreements	493,000	1,109,000	12,000
Difference between income tax expense computed using statutory federal income tax rate and effective rate [Abstract]
Statutory federal income tax	5,161,000	(49,808,000)	27,221,000
Non-deductible goodwill impairment expense	0	61,785,000	0
State income taxes, less federal income tax benefit	453,000	1,520,000	3,318,000
Permanent items	389,000	434,000	(477,000)
Change in valuation allowance	285,000	972,000	337,000
Prior year tax adjustments	263,000	150,000	(55,000)
Other	171,000	333,000	101,000
Income tax expense	6,722,000	15,386,000	30,445,000
Income Tax Contingency [Line Items]
Unrecognized tax benefits that affect our effective tax rate	1,300,000	1,400,000
Reduction resulting from lapse of applicable statute of Limitations	1,100,000
Changes in unrecognized tax benefits [Roll Forward]
Balance, beginning of period	1,392,000	1,072,000
Increases based upon tax positions related to prior years		320,000
Decreases based upon tax positions related to prior years	(44,000)
Balance, end of period	1,348,000	1,392,000	1,072,000
International [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	12,400,000
Changes in unrecognized tax benefits [Roll Forward]
Open tax year	2009
Federal [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	11,000,000
Operating loss carryforwards, expiration dates	2021
Changes in unrecognized tax benefits [Roll Forward]
Open tax year	2009
State [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 16,000,000
Changes in unrecognized tax benefits [Roll Forward]
Open tax year	2009