Leases (Components of Operating Lease Costs) (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Operating Lease Expense		$ 5,268	$ 4,129
Variable Lease Expense	[1]	537	525
Short-Term Lease Expense/Costs	[2]	1,279	918
Sublease Income		(356)	(297)
Total Lease Expense		6,728	5,275
Oil and Natural Gas Properties [Member]
Lessee, Lease, Description [Line Items]
Short-Term Lease Expense/Costs	[3]	$ 14,188	$ 19,232

[1] Variable lease payments that are not dependent on an index or rate are not included in the lease liability.

[2] Short-term lease costs exclude expenses related to leases with a lease term of one month or less.

[3] Short-term lease costs relating to drilling rig leases that are capitalized as part of oil and natural gas properties under full cost pool accounting.