Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 95,619	$ 134,565
Trade accounts receivable, net of allowance of $3,004 and $2,780, respectively	227,222	209,100
Accounts receivable-related parties	52	52
Income tax receivable	3,344	2,553
Inventories	40,072	40,230
Prepaid expenses	11,495	8,796
Other current assets	8,223	13,891
Deferred tax assets	32,321	29,113
Total current assets	418,348	438,300
Property and equipment, net	952,219	943,766
Deferred debt costs, net of amortization	17,340	18,733
Goodwill	110,556	105,836
Other intangible assets, net of amortization	84,240	82,762
Other assets	6,292	6,521
Total assets	1,588,995	1,595,918
Current liabilities:
Accounts payable	56,866	61,740
Accrued expenses	91,420	77,716
Current portion of long-term debt	39,772	38,235
Other current liabilities	427	306
Total current liabilities	188,485	177,997
Long-term debt, net of unamortized premium on notes of $1,574 and $1,683, respectively	847,644	844,906
Deferred tax liabilities	177,554	185,101
Other long-term liabilities	19,737	13,667
Commitments and contingencies
Stockholders' equity:
Preferred stock; $0.01 par value; 5,000,000 shares authorized; none designated or issued at June 30, 2013 and December 31, 2012
Common stock; $0.01 par value; 80,000,000 shares authorized; 43,500,032 shares issued and 42,224,927 shares outstanding at June 30, 2013; 43,500,032 shares issued and 41,721,299 shares outstanding at December 31, 2012	435	435
Additional paid-in capital	354,741	355,687
Retained earnings	12,939	34,513
Treasury stock, at cost, 1,275,105 and 1,778,803 shares at June 30, 2013 and December 31, 2012, respectively	(12,540)	(16,388)
Total stockholders' equity	355,575	374,247
Total liabilities and stockholders' equity	$ 1,588,995	$ 1,595,918