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Acquisitions and Dispositions of Businesses (Acquisitions) (Narrative) (Details)	1 Months Ended				9 Months Ended		12 Months Ended
	Jul. 31, 2026 business	Mar. 31, 2026 business	Oct. 31, 2025 USD ($) business	Jun. 30, 2025 business	Sep. 30, 2026 business	Sep. 30, 2025 USD ($)	Dec. 31, 2025 USD ($) business	Jul. 31, 2025
Business Combination [Line Items]
Number of businesses acquired \| business					2		5
Acquisition purchase price \| $							$ 71,200,000
Net pension obligations \| $							107,500,000
Acquisition-related costs \| $						$ 2,000,000.0
Goodwill expected to be deductible for income tax purposes \| $							$ 12,400,000
Graham Healthcare Group [Member] \| Other Healthcare Businesses [Member]
Business Combination [Line Items]
Number of businesses acquired \| business	1	1	2				2
Education Division [Member]
Business Combination [Line Items]
Number of businesses acquired \| business							1
Education Division [Member] \| Supplemental Education [Member]
Business Combination [Line Items]
Number of businesses acquired \| business				1
Manufacturing [Member]
Business Combination [Line Items]
Number of businesses acquired \| business							1
Automotive [Member]
Business Combination [Line Items]
Number of businesses acquired \| business							1
Arconic Architectural Products, LLC [Member] \| Manufacturing [Member] \| Hoover Treated Wood Products [Member]
Business Combination [Line Items]
Percentage of interest acquired								100.00%
Honda auto dealership [Member] \| Automotive [Member]
Business Combination [Line Items]
Floor plan payables \| $			$ 4,900,000
Honda auto dealership [Member] \| Delayed Draw Term Loan [Member] \| Automotive [Member]
Business Combination [Line Items]
Amount borrowed to finance business acquisition \| $			$ 38,700,000