Properties And Equipment - Summary of Property Acquisitions (Details) $ in Millions		3 Months Ended
		Dec. 31, 2022 USD ($) a	Dec. 31, 2021 USD ($) a shares
Haynesville / LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	68	426
Cash		$ 0.9	$ 5.8
Total Purchase Price	[2]	$ 0.9	$ 5.8
Haynesville / LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	187	847
Cash		$ 2.6	$ 0.6
Number of shares | shares	[3]		1,519,481
Total Purchase Price	[2]	$ 2.6	$ 4.1
SCOOP / OK [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	71	172
Cash		$ 0.9	$ 1.4
Total Purchase Price	[2]	$ 0.9	$ 1.4
Haynesville / LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	144
Cash		$ 1.7
Total Purchase Price	[2]	$ 1.7
Haynesville /LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	18
Cash		$ 0.2
Total Purchase Price	[2]	$ 0.2
Haynesville / LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	46
Cash		$ 0.5
Total Purchase Price	[2]	$ 0.5
SCOOP / OK [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	50	220
Cash		$ 0.6	$ 1.2
Total Purchase Price	[2]	$ 0.6	$ 1.2
SCOOP / OK [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	98
Cash		$ 1.1
Total Purchase Price	[2]	$ 1.1
Haynesville /LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	114
Cash		$ 1.2
Total Purchase Price	[2]	$ 1.2
Haynesville /LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	155
Cash		$ 1.6
Total Purchase Price	[2]	$ 1.6
Haynesville / TX [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	11	103
Cash		$ 0.2	$ 0.6
Total Purchase Price	[2]	$ 0.2	$ 0.6
Haynesville /LA [Member]
Property Plant And Equipment [Line Items]
Net royalty acres | a	[1],[2]	295	116
Cash		$ 3.1	$ 1.7
Total Purchase Price	[2]	$ 3.1	$ 1.7

[1] An estimated net royalty equivalent was used for the minerals included in the net royalty acres.

[2] Excludes subsequent closing adjustments and insignificant acquisitions.

[3] The Company’s policy is to classify all costs associated with equity issuances as financial costs in the Statements of Cash Flows.