Notes and Contracts Payable (Tables)

12 Months Ended

Dec. 31, 2023

Debt Disclosure [Abstract]

Schedule of Notes and Contracts Payable

	December 31,
	2023			2022
	(dollars in millions)
2.40% senior unsecured notes due August 15, 2031, effective interest rate of 2.44%	$	650.0		$	650.0
4.00% senior unsecured notes due May 15, 2030, effective interest rate of 4.05%		450.0			450.0
4.60% senior unsecured notes due November 15, 2024, effective interest rate of      4.60%		300.0			300.0
4.30% senior unsecured notes due February 1, 2023, effective interest rate of 4.35%		—			250.0
Trust deed note due November 1, 2023, interest rate of 5.26%		—			4.0
Other notes and contracts payable with maturities through 2028, weighted    -average interest rates of 3.41% and 3.30% at December 31, 2023 and 2022,    respectively		4.2			3.8
		1,404.2			1,657.8
Unamortized discounts and debt issuance costs		(10.3	)		(12.0	)
	$	1,393.9		$	1,645.8

Aggregate Annual Maturities of Notes and Contracts Payable

The aggregate annual maturities for notes and contracts payable for the next five years and thereafter are summarized as follows:

Year	Annual maturities
	(in millions)
2024	$	301.7
2025		1.3
2026		0.8
2027		0.3
2028		0.1
Thereafter		1,100.0
	$	1,404.2