Acquisitions Assets Acquired and Liabilities Assumed (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 16, 2013	Feb. 09, 2012	May 31, 2012	Jun. 19, 2013
Business Acquisition [Line Items]
Goodwill	$ 30,864	$ 67,530	$ 53,093
Black Hawk
Business Acquisition [Line Items]
Accounts receivable				10,114
Prepaid expenses and other current assets				319
Property and equipment				30,088
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles				12,210
Accounts payable				(1,584)
Accrued expenses				(2,160)
Total net identifiable assets				48,987
Goodwill				10,576
Net assets acquired				59,563
Eagle Well
Business Acquisition [Line Items]
Property and equipment					23,842
Identifiable intangible assets					14,300
Accrued expenses					(137)
Total net identifiable assets					38,005
Goodwill					10,126
Net assets acquired					48,131
Sun Well
Business Acquisition [Line Items]
Cash						3,561
Accounts receivable						7,233
Prepaid expenses and other current assets						782
Property and equipment						29,787
Identifiable intangible assets						27,300
Other long-term assets						714
Accounts payable						(1,036)
Accrued expenses						(2,030)
Other long-term liabilities						(1,805)
Long-term debt						(16,000)
Capital lease obligations						(1,622)
Deferred tax liabilities						(16,539)
Total net identifiable assets						30,345
Goodwill						38,401
Net assets acquired						68,746
UK Elite
Business Acquisition [Line Items]
Cash							1,126
Marketable securities							194
Accounts receivable							637
Prepaid expenses and other current assets							759
Identifiable intangible assets							1,050
Other long-term assets							53
Accrued expenses							(2,577)
Deferred tax liabilities							(447)
Total net identifiable assets							795
Goodwill							2,018
Non-controlling interest							(563)
Net assets acquired							$ 2,250