Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 15,028	$ 164,203
Short-term investments (Note 3)	39,939	40,000
Restricted cash	0	345
Accounts receivable, net (Note 4)	254,799	186,001
Income tax receivable	4,903	9,443
Inventories	17,916	13,276
Prepaid and other current assets	9,609	3,542
Deferred income taxes (Note 9)	0	26,488
Total current assets	342,194	443,298
Property and equipment, net (Note 5)	350,725	338,778
Goodwill	1,389,965	1,258,065
Other (Note 6)	34,776	7,690
Total assets	2,117,660	2,047,831
Current liabilities:
Current installments of long-term obligations (Note 8)	397,132	619
Accounts payable	53,294	64,078
Accrued expenses:
Compensation and benefits	33,142	39,500
Liability insurance	19,990	19,052
Other current liabilities (Note 10)	54,316	51,501
Deferred income taxes (Note 9)	8,769	0
Total current liabilities	566,643	174,750
Long-term obligations, excluding current installments (Note 8)	256,778	494,271
Deferred income taxes and other taxes (Note 9)	408,325	381,061
Total liabilities	1,231,746	1,050,082
Commitments and contingencies (Notes 7, 8 and 16)
Stockholders' equity (Notes 8, 9, 11, 12 and 14):
Common stock, $.01 par value. Authorized 200,000,000 shares; issued and outstanding: 87,026,945 in 2011 and 96,270,308 in 2010	870	963
Additional paid-in capital	707,080	681,988
Retained earnings	177,964	314,798
Total stockholders' equity	885,914	997,749
Total liabilities and stockholders' equity	$ 2,117,660	$ 2,047,831