Guarantor Financial Information (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Condensed consolidating financial statements
Current assets	$ 135,470	$ 138,311
Property and equipment, net	1,285,171	1,199,107
Investments in subsidiaries	0	0
Other assets	29,905	29,319
Total assets	1,450,546	1,366,737	1,379,710
Current liabilities	156,204	136,395
Non-current liabilities:
Long-term debt	631,682	639,638
Deferred income taxes	164,635	140,809
Other	95,964	96,112
TOTAL NON-CURRENT LIABILITIES	892,281	876,559
Equity	402,061	353,783
Total liabilities and equity	1,450,546	1,366,737
Issuer
Condensed consolidating financial statements
Current assets	139,510	140,100
Property and equipment, net	916,037	833,980
Investments in subsidiaries	364,874	342,416
Other assets	16,441	16,032
Total assets	1,436,862	1,332,528
Current liabilities	341,379	290,327
Non-current liabilities:
Long-term debt	631,682	639,638
Deferred income taxes	123,726	118,438
Other	43,832	36,161
TOTAL NON-CURRENT LIABILITIES	799,240	794,237
Equity	296,243	247,964
Total liabilities and equity	1,436,862	1,332,528
Guarantor Subsidiaries
Condensed consolidating financial statements
Current assets	293,188	248,314
Property and equipment, net	351,069	351,171
Investments in subsidiaries	0	0
Other assets	13,464	13,287
Total assets	657,721	612,772
Current liabilities	110,873	93,055
Non-current liabilities:
Long-term debt	0	0
Deferred income taxes	143,830	129,880
Other	51,958	59,829
TOTAL NON-CURRENT LIABILITIES	195,788	189,709
Equity	351,060	330,008
Total liabilities and equity	657,721	612,772
Non-Guarantor Subsidiaries
Condensed consolidating financial statements
Current assets	646	538
Property and equipment, net	18,065	13,956
Investments in subsidiaries	0	0
Other assets	0	0
Total assets	18,711	14,494
Current liabilities	979	976
Non-current liabilities:
Long-term debt	0	0
Deferred income taxes	3,744	988
Other	174	122
TOTAL NON-CURRENT LIABILITIES	3,918	1,110
Equity	13,814	12,408
Total liabilities and equity	18,711	14,494
Adjustments/Eliminations
Condensed consolidating financial statements
Current assets	(297,874)	(250,641)
Property and equipment, net	0	0
Investments in subsidiaries	(364,874)	(342,416)
Other assets	0	0
Total assets	(662,748)	(593,057)
Current liabilities	(297,027)	(247,963)
Non-current liabilities:
Long-term debt	0	0
Deferred income taxes	(106,665)	(108,497)
Other	0	0
TOTAL NON-CURRENT LIABILITIES	(106,665)	(108,497)
Equity	(259,056)	(236,597)
Total liabilities and equity	$ (662,748)	$ (593,057)