KW Unsecured Debt - Schedule of Unsecured Debt (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
KW unsecured debt
Debt Instrument [Line Items]
Debt (excluding loan fees)	$ 1,952.4	$ 2,085.5
Unamortized loan fees	(21.1)	(22.9)
Total debt	1,931.3	2,062.6
Unamortized discount (premium)	(3.3)	(3.5)
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Debt (excluding loan fees)	149.1	282.0
2029 Notes | Revolving Credit Facility
Debt Instrument [Line Items]
Debt (excluding loan fees)	601.6	601.7
2030 Notes | Revolving Credit Facility
Debt Instrument [Line Items]
Debt (excluding loan fees)	600.0	600.0
2031 Notes | Revolving Credit Facility
Debt Instrument [Line Items]
Debt (excluding loan fees)	$ 601.7	$ 601.8