Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
REVENUES:
Contract drilling	$ 260,062	$ 242,321	$ 533,619	$ 477,115
Revenues related to reimbursable expenses	13,035	10,840	24,184	21,139
Total revenues	273,097	253,161	557,803	498,254
COSTS AND EXPENSES:
Contract drilling	136,966	98,561	260,128	204,499
Reimbursable expenses	9,188	8,912	17,602	14,890
Depreciation	37,231	28,482	69,775	56,060
General and administrative	15,022	13,268	34,844	30,489
Gain on sale of equipment	(34,443)	0	(34,079)	0
Other, net	399	(20)	(1,602)	(13)
Total costs and expenses	164,363	149,203	346,668	305,925
OPERATING INCOME	108,734	103,958	211,135	192,329
OTHER INCOME (EXPENSE):
Interest expense, net of capitalized interest	(11,502)	(6,547)	(19,713)	(10,955)
Interest income	51	21	121	145
Other income (expense) total	(11,451)	(6,526)	(19,592)	(10,810)
INCOME BEFORE INCOME TAXES	97,283	97,432	191,543	181,519
PROVISION FOR INCOME TAXES	23,983	11,913	34,846	23,169
NET INCOME	$ 73,300	$ 85,519	$ 156,697	$ 158,350
EARNINGS PER COMMON SHARE (NOTE 2):
Basic (in dollars per share)	$ 1.14	$ 1.30	$ 2.44	$ 2.41
Diluted (in dollars per share)	$ 1.13	$ 1.28	$ 2.41	$ 2.39
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING (NOTE 2):
Basic (in shares)	64,238	65,733	64,175	65,631
Diluted (in shares)	65,031	66,589	65,028	66,341