Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Operating revenues:
Drilling - U.S. Land	$ 1,439,523	$ 1,242,462	$ 2,523,518
Drilling - Offshore	136,263	138,601	241,666
Drilling - International Land	212,972	229,894	382,331
Other	15,983	13,275	14,187
Total operating revenues	1,804,741	1,624,232	3,161,702
Operating costs and expenses:
Operating costs, excluding depreciation and amortization	1,249,317	898,805	1,703,476
Depreciation and amortization	585,543	598,587	608,039
Asset impairment charge		6,250	39,242
Research and development	12,047	10,269	16,104
General and administrative	151,002	146,183	134,712
Income from asset sales	(20,627)	(9,896)	(11,834)
Total operating costs and expenses	1,977,282	1,650,198	2,489,739
Operating income (loss) from continuing operations	(172,541)	(25,966)	671,963
Other income (expense):
Interest and dividend income	5,915	3,166	5,840
Interest expense	(19,747)	(22,913)	(15,023)
Loss on investment securities		(25,989)
Other	1,775	(965)	(901)
Total other income (expense)	(12,057)	(46,701)	(10,084)
Income (loss) from continuing operations before income taxes	(184,598)	(72,667)	661,879
Income tax provision (benefit)	(56,735)	(19,677)	241,405
Income (loss) from continuing operations	(127,863)	(52,990)	420,474
Income (loss) from discontinued operations before income taxes	3,285	2,360	(124)
Income tax provision (benefit)	3,634	6,198	(77)
Loss from discontinued operations	(349)	(3,838)	(47)
NET INCOME (LOSS)	$ (128,212)	$ (56,828)	$ 420,427
Basic earnings per common share:
Income (loss) from continuing operations (in dollars per share)	$ (1.20)	$ (0.50)	$ 3.88
Loss from discontinued operations (in dollars per share)		(0.04)
Net income (loss) (in dollars per share)	(1.20)	(0.54)	3.88
Diluted earnings per common share:
Income (loss) from continuing operations (in dollars per share)	(1.20)	(0.50)	3.85
Loss from discontinued operations (in dollars per share)		(0.04)
Net income (loss) (in dollars per share)	$ (1.20)	$ (0.54)	$ 3.85
Weighted average shares outstanding (in thousands):
Basic (in shares)	108,500	107,996	107,754
Diluted (in shares)	108,500	107,996	108,570