EMPLOYEE BENEFIT PLANS (Details 3) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Change in plan assets
Fair value of plan assets at beginning of year	$ 86,718,000	$ 67,284,000
Fair value of plan assets at end of year	96,818,000	86,718,000	67,284,000
DEFINED CONTRIBUTION PLAN
Percentage of employer's contribution under 401(k)/ Thrift Plan matching the first 5 percent of participant's compensation subject to certain limitations	100.00%
Percentage of participant's compensation eligible for employer's matching contribution	5.00%
Annual expense incurred for defined contribution plan	28,300,000	26,700,000	21,000,000
Oil and Gas Properties
Change in plan assets
Fair value of plan assets at beginning of year	299,000	275,000
Unrealized gains (losses) relating to property still held at the reporting date	(12,000)	24,000
Fair value of plan assets at end of year	$ 287,000	$ 299,000