Capital Stock - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Jun. 30, 2024	Dec. 31, 2024
Capital Unit [Line Items]
Preferred stock, par value (dollars per share)	$ 50,000			$ 50,000
Cumulative preferred stock (percent)	4.50%		4.50%
Treasury shares, at cost	$ 413,812,000			$ 398,204,000
Common stock, shares authorized (shares)	180,000,000
Common stock, shares, outstanding (shares)	39,298,861			39,260,080
Treasury stock, common, shares (shares)	22,782,530			22,821,311
Preferred stock
Capital Unit [Line Items]
Treasury shares, at cost	$ 1,800,000
Cumulative Preferred Stock
Capital Unit [Line Items]
Preferred stock, shares authorized (shares)	100,000
Preferred stock, par value (dollars per share)	$ 50
Cumulative preferred stock (percent)	4.50%
Preferred stock, callable price per share (dollars per share)	$ 52.50
Preferred stock, shares issued (shares)	71,340			71,340
Treasury stock, preferred, shares (shares)	52,998			52,998
Purchase of treasury shares (shares)	0	0
Second Cumulative Preferred Voting Stock
Capital Unit [Line Items]
Preferred stock, shares authorized (shares)	1,000,000
Preferred stock, par value (dollars per share)	$ 10
Preferred stock, shares issued (shares)	0			0
Common Stock
Capital Unit [Line Items]
Purchase of treasury shares (shares)	62,125	0
Common stock, shares issued (shares)	62,081,391			62,081,391
Stock issued during period, new issues (shares)	0	0
Common stock, value, issued (up to)	$ 200,000,000.0
Treasury stock
Capital Unit [Line Items]
Reissued shares (shares)	153,734	95,428