Borrowings - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended	6 Months Ended
	Jun. 01, 2022	Jun. 01, 2012	Jan. 31, 2010	Mar. 31, 2026	Mar. 30, 2026	Sep. 30, 2025	Mar. 31, 2025
Debt Instrument [Line Items]
Debt repurchased				$ 0			$ 0
Junior Subordinated Notes
Debt Instrument [Line Items]
Unamortized accretion				$ 21,270		$ 22,303
Junior Subordinated Notes
Debt Instrument [Line Items]
Weighted average fixed interest rate of debt				6.38%
Aggregate principle balance of notes				$ 100,800
Junior Subordinated Debt, Modified Terms
Debt Instrument [Line Items]
Aggregate principal amount of debt			$ 75,000
Variable rate floor			4.25%
Variable rate cap			9.25%
Redemption price percentage		75.00%
Annual increase of percentage of principal amount redeemable	1.785%
Junior Subordinated Debt, Original Terms
Debt Instrument [Line Items]
Aggregate principal amount of debt				25,800
Junior Subordinated Debt, Original Terms | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate			2.71%
Senior Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity, including letters of credit				625,000
Credit facility, available increase in borrowing capacity				100,000
Senior unsecured revolving credit facility				195,000		$ 0
Letters of credit secured using cash collateral				45,300
Amount of available borrowings under the secured revolving credit facility				$ 284,700
Weighted average fixed interest rate of debt				8.01%
Senior Unsecured Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Percent of commitment fee on unused portion				0.25%
Senior Unsecured Revolving Credit Facility | Minimum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate				2.15%
Senior Unsecured Revolving Credit Facility | Minimum | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate				1.15%
Senior Unsecured Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Percent of commitment fee on unused portion				0.40%
Senior Unsecured Revolving Credit Facility | Maximum | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate				2.90%
Senior Unsecured Revolving Credit Facility | Maximum | Alternate Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate				1.90%
Senior Unsecured Revolving Credit Facility | Senior Notes
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity, including letters of credit				$ 525,000	$ 365,000
Letter of Credit | Senior Notes
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity, including letters of credit				$ 100,000