Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Operating revenues:
Drilling - U.S. Land	$ 1,242,462	$ 2,523,518	$ 3,099,954
Drilling - Offshore	138,601	241,666	251,341
Drilling - International Land	229,894	382,331	351,263
Other	13,275	14,187	13,410
Total operating revenues	1,624,232	3,161,702	3,715,968
Operating costs and expenses
Operating costs, excluding depreciation	898,805	1,703,476	2,006,715
Depreciation	598,587	608,039	523,984
Asset impairment charge	6,250	39,242
Research and development	10,269	16,104	15,905
General and administrative	146,183	134,712	135,273
Income from asset sales	(9,896)	(11,834)	(19,083)
Total operating costs and expenses	1,650,198	2,489,739	2,662,794
Operating income (loss) from continuing operations	(25,966)	671,963	1,053,174
Other income (expense)
Interest and dividend income	3,166	5,840	1,543
Interest expense	(22,913)	(15,023)	(4,657)
Gain (loss) on investment securities	(25,989)		45,234
Other	(965)	(901)	(636)
Total other income (expense)	(46,701)	(10,084)	41,484
Income (loss) from continuing operations before income taxes	(72,667)	661,879	1,094,658
Income tax provision (benefit)	(19,677)	241,405	388,048
Income (loss) from continuing operations	(52,990)	420,474	706,610
Income (loss) from discontinued operations before income taxes	2,360	(124)	2,758
Income tax provision (benefit)	6,198	(77)	2,805
Loss from discontinued operations	(3,838)	(47)	(47)
NET INCOME (LOSS)	$ (56,828)	$ 420,427	$ 706,563
Basic earnings per common share:
Income (loss) from continuing operations (in dollars per share)	$ (0.50)	$ 3.88	$ 6.52
Loss from discontinued operations (in dollars per share)	(0.04)
Net income (loss) (in dollars per share)	(0.54)	3.88	6.52
Diluted earnings per common share:
Income (loss) from continuing operations (in dollars per share)	(0.50)	3.85	6.44
Loss from discontinued operations (in dollars per share)	(0.04)
Net income (loss) (in dollars per share)	$ (0.54)	$ 3.85	$ 6.44
Weighted average shares outstanding (in thousands):
Basic (in shares)	107,996	107,754	107,800
Diluted (in shares)	107,996	108,570	109,141