CONSOLIDATED CONDENSED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 38,594	$ 249,509
Accounts receivable, net of allowance for doubtful accounts of $3,665 and $3,674 at September 30, 2014 and December 31, 2013, respectively	593,373	451,517
Inventory	29,162	21,248
Deferred tax assets, net	32,322	32,952
Other	54,645	53,424
Total current assets	748,096	808,650
Property and equipment, net	3,907,331	3,635,541
Goodwill and intangible assets	180,223	167,470
Deposits on equipment purchases	112,288	52,560
Other	20,411	22,906
Total assets	4,968,349	4,687,127
Current liabilities:
Accounts payable	370,127	173,150
Federal and state income taxes payable	24,378	10,670
Accrued expenses	182,944	160,457
Current portion of long-term debt	10,000	10,000
Total current liabilities	587,449	354,277
Long-term debt	675,000	682,500
Deferred tax liabilities, net	836,404	887,864
Other	10,036	6,489
Total liabilities	2,108,889	1,931,130
Commitments and contingencies (see Note 9)
Stockholders' equity:
Preferred stock, par value $.01; authorized 1,000,000 shares, no shares issued
Common stock, par value $.01; authorized 300,000,000 shares with 189,233,429 and 186,487,246 issued and 146,414,844 and 144,219,189 outstanding at September 30, 2014 and December 31, 2013, respectively	1,892	1,865
Additional paid-in capital	977,425	913,505
Retained earnings	2,768,868	2,707,439
Accumulated other comprehensive income	10,310	14,076
Treasury stock, at cost, 42,818,585 shares and 42,268,057 shares at September 30, 2014 and December 31, 2013, respectively	(899,035)	(880,888)
Total stockholders' equity	2,859,460	2,755,997
Total liabilities and stockholders' equity	$ 4,968,349	$ 4,687,127