Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating revenues
Drilling services	$ 244,781	$ 611,398
Other	1,596	3,259
Total operating revenues	246,377	614,657
Operating costs and expenses
Drilling services operating expenses, excluding depreciation and amortization	198,689	399,329
Other operating expenses	1,362	1,422
Depreciation and amortization	106,861	130,131
Research and development	5,583	6,878
Selling, general and administrative	39,303	49,808
Restructuring charges	138	0
Gain on sale of assets	(12,336)	(4,279)
Total operating costs and expenses	339,600	583,289
Operating income (loss) from continuing operations	(93,223)	31,368
Other income (expense)
Interest and dividend income	1,879	2,214
Interest expense	(6,139)	(6,100)
Gain on investment securities	2,924	2,821
Gain on sale of subsidiary	0	14,963
Other	(1,480)	(399)
Total other income (expense)	(2,816)	13,499
Income (loss) from continuing operations before income taxes	(96,039)	44,867
Income tax provision (benefit)	(18,115)	14,138
Income (loss) from continuing operations	(77,924)	30,729
Income from discontinued operations before income taxes	7,493	7,457
Income tax provision	0	7,581
Income (loss) from discontinued operations	7,493	(124)
Net income (loss)	$ (70,431)	$ 30,605
Basic income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	$ (0.73)	$ 0.27
Income from discontinued operations (in dollars per share)	0.07	0
Net income (loss) (in dollars per share)	(0.66)	0.27
Diluted income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	(0.73)	0.27
Income from discontinued operations (in dollars per share)	0.07	0
Net income (loss) (in dollars per share)	$ (0.66)	$ 0.27
Weighted average shares outstanding:
Basic (in shares)	107,617	108,555
Diluted (in shares)	107,617	108,724