Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Operating revenues:
Contract drilling	$ 2,449,051	$ 1,788,758	$ 1,610,957
Other	38,217	15,983	13,275
Total operating revenues	2,487,268	1,804,741	1,624,232
Operating costs and expenses:
Contract drilling operating expenses, excluding depreciation and amortization	1,626,387	1,242,605	892,748
Operating expenses applicable to other revenues	26,223	6,712	6,057
Depreciation and amortization	583,802	585,543	598,587
Research and development	18,167	12,047	10,269
Selling, general and administrative	200,619	151,002	146,183
Asset impairment charge	23,128		6,250
Gain on sale of assets	(22,660)	(20,627)	(9,896)
Total operating costs and expenses	2,455,666	1,977,282	1,650,198
Operating income (loss) from continuing operations	31,602	(172,541)	(25,966)
Other income (expense)
Interest and dividend income	8,017	5,915	3,166
Interest expense	(24,265)	(19,747)	(22,913)
Loss on investment securities	1		(25,989)
Other	486	1,775	(965)
Total other income (expense)	(15,761)	(12,057)	(46,701)
Income (loss) from continuing operations before income taxes	15,841	(184,598)	(72,667)
Income tax benefit	(477,169)	(56,735)	(19,677)
Income (loss) from continuing operations	493,010	(127,863)	(52,990)
Income from discontinued operations before income taxes	23,389	3,285	2,360
Income tax provision	33,727	3,634	6,198
Loss from discontinued operations	(10,338)	(349)	(3,838)
Net Income (Loss)	$ 482,672	$ (128,212)	$ (56,828)
Basic earnings per common share:
Income (loss) from continuing operations (in dollars per share)	$ 4.49	$ (1.20)	$ (0.50)
Loss from discontinued operations (in dollars per share)	(0.10)		(0.04)
Net income (loss) (in dollars per share)	4.39	(1.20)	(0.54)
Diluted earnings per common share:
Income (loss) from continuing operations (in dollars per share)	4.47	(1.20)	(0.50)
Loss from discontinued operations (in dollars per share)	(0.10)		(0.04)
Net income (loss) (in dollars per share)	$ 4.37	$ (1.20)	$ (0.54)
Weighted average shares outstanding (in thousands):
Basic (in shares)	108,851	108,500	107,996
Diluted (in shares)	109,387	108,500	107,996