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

[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.