Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
REVENUES:
Contract drilling	$ 253,161	$ 171,621	$ 498,254	$ 356,293
COSTS AND EXPENSES:
Contract drilling	107,473	79,342	219,389	157,686
Depreciation	28,482	15,406	56,060	30,769
General and administrative	13,268	11,552	30,489	25,646
Other, net	(20)	863	(13)	863
Total costs and expenses	149,203	107,163	305,925	214,964
OPERATING INCOME	103,958	64,458	192,329	141,329
OTHER INCOME (EXPENSE):
Interest expense, net of capitalized interest	(6,547)	(1,080)	(10,955)	(1,683)
Interest income	21	114	145	200
Other	0	0	0	1,577
Other income (expense) total	(6,526)	(966)	(10,810)	94
INCOME BEFORE INCOME TAXES	97,432	63,492	181,519	141,423
PROVISION FOR INCOME TAXES	11,913	4,026	23,169	16,489
NET INCOME	$ 85,519	$ 59,466	$ 158,350	$ 124,934
EARNINGS PER COMMON SHARE (NOTE 2):
Basic (in dollars per share)	$ 1.30	$ 0.91	$ 2.41	$ 1.92
Diluted (in dollars per share)	$ 1.28	$ 0.90	$ 2.39	$ 1.90
AVERAGE COMMON SHARES OUTSTANDING (NOTE 2):
Basic (in shares)	65,733	65,276	65,631	65,150
Diluted (in shares)	66,589	65,781	66,341	65,660