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Significant Transactions - Distinguished Programs (Details) - USD ($) $ in Millions				3 Months Ended			6 Months Ended
	May 01, 2026	Nov. 01, 2025	Sep. 02, 2025	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Other Significant Transactions [Line Items]
Acquisition of businesses				$ 180.6		$ 95.4	$ 180.6	$ 95.4
Distinguished
Other Significant Transactions [Line Items]
Basic units outstanding percentage				31.30%			31.30%
Subsidiary - Distinguished Managing General Agent
Other Significant Transactions [Line Items]
Basic ownership			55.50%	55.30%			55.30%		55.50%
Business combination, basic ownership interest acquired, percentage			1.70%
Ownership percentage, fully diluted			43.60%	43.30%			43.30%		43.60%
Subsidiary, ownership percentage economic interest falls			50.00%
Subsidiary - Distinguished Managing General Agent \| Distinguished Management
Other Significant Transactions [Line Items]
Ownership percentage, fully diluted			24.70%
Ownership percentage of basic units outstanding			4.20%
Distinguished Transaction
Other Significant Transactions [Line Items]
Business combination, consideration transferred			$ 224.8
Post-closing purchase price adjustment			0.5
Business combination, consideration transferred, liabilities incurred			50.0
Cash on hand			$ 6.8
Redemption value				$ 131.5			$ 131.5
Business combination, right to purchase units			1.35
Assets and goodwill acquired			$ 745.1
Goodwill			620.0
Liabilities acquired			250.9
Redeemable noncontrolling interest			133.5
Nonredeemable noncontrolling interest			73.8
Goodwill, intangible assets and other liabilities acquired, measurement period adjustment					$ 1.2
Transaction costs			6.8
Other intangible assets			$ 198.2
Distinguished Transaction, ScaleCo Program
Other Significant Transactions [Line Items]
Business combination, consideration transferred		$ 33.6
Acquisition of businesses		23.6
Other intangible assets		$ 9.3
Hawkeye Electric, LLC
Other Significant Transactions [Line Items]
Business combination, consideration transferred	$ 67.2
Cash on hand	5.9
Assets and goodwill acquired	85.5
Liabilities acquired	12.4
Transaction costs	2.1
Acquisition of businesses	$ 54.6