Significant Accounting Policies and Practices - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($) partnership variable_interest_entity voting_interest_model_entity	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Significant Accounting Policies and Practices
Assets related to consolidated VIEs	$ 1,089.1		$ 1,116.2
Liabilities related to consolidated VIEs	853.9		894.1
Restricted cash and cash equivalents	$ 0.8		0.2
Number of ownership interest entities | partnership	31
Investments under the equity method of accounting	$ 11.3		10.8
Equity earnings in related investments	$ 0.9	$ 0.1
ASU 2021-10
Significant Accounting Policies and Practices
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
ASU 2021-08
Significant Accounting Policies and Practices
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2022
Minimum
Significant Accounting Policies and Practices
Ownership interests percentage	30.00%
Maximum
Significant Accounting Policies and Practices
Ownership interests percentage	50.00%
Primary Beneficiary
Significant Accounting Policies and Practices
Assets related to consolidated VIEs	$ 55.3		54.9
Liabilities related to consolidated VIEs	$ 52.6		$ 52.7
Number of ownership interest entities | variable_interest_entity	25
Not Primary Beneficiary
Significant Accounting Policies and Practices
Number of ownership interest entities | voting_interest_model_entity	6