CONSOLIDATED CONDENSED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Operating revenues:
Drilling - U.S. Land	$ 658,804	$ 495,459	$ 1,276,583	$ 972,277
Drilling - Offshore	43,421	50,586	94,213	95,453
Drilling - International Land	64,088	54,684	124,823	123,638
Other	3,669	3,677	6,951	7,680
Total operating revenues	769,982	604,406	1,502,570	1,199,048
Operating costs and other:
Operating costs, excluding depreciation	448,208	340,039	839,240	670,085
Depreciation	90,934	76,161	177,222	149,341
General and administrative	27,805	24,406	53,968	44,295
Research and development	3,830	3,640	7,079	7,110
Income from asset sales	(7,820)	(4,105)	(12,503)	(6,774)
Total operating costs and other	562,957	440,141	1,065,006	864,057
Operating income from continuing operations	207,025	164,265	437,564	334,991
Other income (expense):
Interest and dividend income	356	356	692	670
Interest expense	(2,421)	(5,513)	(4,882)	(9,964)
Other	(42)	232	(21)	398
Total other income (expense)	(2,107)	(4,925)	(4,211)	(8,896)
Income from continuing operations before income taxes	204,918	159,340	433,353	326,095
Income tax provision	75,155	60,379	159,293	122,769
Income from continuing operations	129,763	98,961	274,060	203,326
Loss from discontinued operations before income taxes	(125)	(176)	(136)	(391)
Income tax provision	(81)	(5)	(81)	(5)
Loss from discontinued operations	(44)	(171)	(55)	(386)
NET INCOME	$ 129,719	$ 98,790	$ 274,005	$ 202,940
Basic earnings per common share:
Income from continuing operations (in dollars per share)	$ 1.20	$ 0.92	$ 2.54	$ 1.90
Net income (in dollars per share)	$ 1.20	$ 0.92	$ 2.54	$ 1.90
Diluted earnings per common share:
Income from continuing operations (in dollars per share)	$ 1.18	$ 0.91	$ 2.51	$ 1.87
Net income (in dollars per share)	$ 1.18	$ 0.91	$ 2.51	$ 1.87
Weighted average shares outstanding:
Basic (in shares)	107,385	106,515	107,285	106,270
Diluted (in shares)	109,042	108,595	108,925	108,375
Dividends declared per common share (in dollars per share)	$ 0.07	$ 0.06	$ 0.14	$ 0.12