Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 316,599	$ 333,765
Marketable securities	1,175,572	902,414
Accounts receivable, net of allowance for bad debts	463,219	563,934
Prepaid expenses and other current assets	143,441	192,570
Total current assets	2,098,831	1,992,683
Drilling and other property and equipment, net of accumulated depreciation	4,835,715	4,667,469
Other assets	245,204	304,005
Total assets	7,179,750	6,964,157
Current liabilities:
Accounts payable	78,312	64,147
Accrued liabilities	322,813	336,400
Taxes payable	31,573	26,744
Total current liabilities	432,698	427,291
Long-term debt	1,496,004	1,495,823
Deferred tax liability	534,767	536,815
Other liabilities	174,851	171,165
Total liabilities	2,638,320	2,631,094
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock (par value $0.01, 500,000,000 shares authorized; 143,947,118 shares issued and 139,030,318 shares outstanding at September 30, 2012; 143,944,009 shares issued and 139,027,209 shares outstanding at December 31, 2011)	1,439	1,439
Additional paid-in capital	1,981,728	1,978,369
Retained earnings	2,669,775	2,472,310
Accumulated other comprehensive gain (loss)	2,901	(4,642)
Treasury stock, at cost (4,916,800 shares at September 30, 2012 and December 31, 2011)	(114,413)	(114,413)
Total stockholders' equity	4,541,430	4,333,063
Total liabilities and stockholders' equity	$ 7,179,750	$ 6,964,157