Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 135,758	$ 80,274	$ 71,082	$ 50,727
Accounts receivable, net of allowance for doubtful accounts of $17,392 and $17,484 at March 31, 2012 and December 31, 2011, respectively	1,035,985	540,602
Prepaid expenses	72,792	34,037
Inventory and other current assets	278,229	228,309
Total current assets	1,522,764	883,222
Property, plant and equipment, net of accumulated depreciation and depletion of $984,221 and $970,137 at March 31, 2012 and December 31, 2011, respectively	2,766,310	1,507,368
Goodwill	2,504,670	581,379
Notes receivable	74,750	73,568
Equity-method investments	69,552	72,472
Intangible and other long-term assets, net of accumulated amortization of $26,755 and $20,620 at March 31, 2012 and December 31, 2011, respectively	530,312	930,136
Total assets	7,468,358	4,048,145
Current liabilities:
Accounts payable	312,985	178,645
Accrued expenses	284,760	197,574
Income taxes payable	40,864	717
Deferred income taxes	16,721	831
Current portion of decommissioning liabilities	15,678	14,956	17,063
Current maturities of long-term debt	20,000	810
Total current liabilities	691,008	393,533
Deferred income taxes	684,894	297,458
Decommissioning liabilities	110,151	108,220	102,321
Long-term debt, net	1,978,508	1,685,087
Other long-term liabilities	104,943	110,248
Stockholders' equity:
Preferred stock of $0.01 par value. Authorized, 5,000,000 shares; none issued
Common stock of $0.001 par value. Authorized - 250,000,000, Issued - 156,920,904, Outstanding - 157, 516,128 at March 31, 2012 Authorized - 125,000,000, Issued and Outstanding, 82,425,443 at December 31, 2011	157	80
Additional paid in capital	2,832,360	447,007
Accumulated other comprehensive income (loss), net	(21,031)	(26,936)
Retained earnings	1,087,368	1,033,448
Total stockholders' equity	3,898,854	1,453,599
Total liabilities and stockholders' equity	$ 7,468,358	$ 4,048,145