Debt (Narrative) (Details)		3 Months Ended		6 Months Ended
		Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 GBP (£)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Average borrowings outstanding		$ 841,800,000	$ 742,100,000	$ 826,900,000	$ 738,300,000
Weighted average interest rate		6.40%	6.00%	6.40%	5.90%
Interest Expense, Net		$ (89,272,000)	$ (10,226,000)	$ (106,422,000)	$ (23,316,000)
Interest expense		91,383,000	11,774,000	110,711,000	26,068,000
5.75% Unsecured Notes maturing in 2026 [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ 1,400,000		$ 1,400,000			$ 1,700,000
Interest rate		5.75%		5.75%		5.75%	5.75%
Fair value of debt instrument		$ 397,800,000		$ 397,800,000			$ 400,400,000
Five-Year Credit Agreement maturing in 2027 [Member]
Debt Instrument [Line Items]
Credit facility current borrowing capacity		300,000,000		300,000,000
Line of credit facility outstanding		132,209,000		132,209,000			97,879,000
USD revolving credit facility borrowings [Member]
Debt Instrument [Line Items]
Line of credit facility outstanding		69,000,000		69,000,000
GBP revolving credit facility borrowings [Member]
Debt Instrument [Line Items]
Line of credit facility outstanding | £						£ 50,000,000
Term Loan maturing in 2027 - $150 million [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		600,000		600,000			600,000
Loans Payable to Bank	[1]	143,739,000		143,739,000			147,476,000
Real Estate Term Loan maturing in 2028 - $75.2 million [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		100,000		100,000			100,000
Loans Payable to Bank	[2]	72,668,000		72,668,000			74,541,000
Capital Term Loan maturing in 2028 - $65 million [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		700,000		700,000			800,000
Loans Payable to Bank	[3]	59,934,000		$ 59,934,000			$ 63,097,000
Secured Overnight Financing Rates (SOFR) [Member] | USD revolving credit facility borrowings [Member]
Debt Instrument [Line Items]
Applicable interest rate margin				1.375%
Prime Rate [Member] | USD revolving credit facility borrowings [Member]
Debt Instrument [Line Items]
Applicable interest rate margin				0.375%
Sterling Overnight Interbank Average Rate (SONIA) [Member] | GBP revolving credit facility borrowings [Member]
Debt Instrument [Line Items]
Applicable interest rate margin				1.375%
Securities Subject to Mandatory Redemption [Member] | Graham Healthcare Group [Member]
Debt Instrument [Line Items]
Interest expense		$ 73,500,000	$ (1,200,000)	$ 75,400,000	$ 300,000

[1] The carrying value is net of $0.6 million of unamortized debt issuance costs as of June 30, 2024 and December 31, 2023.

[2] The carrying value is net of $0.1 million of unamortized debt issuance costs as of June 30, 2024 and December 31, 2023.

[3] The carrying value is net of $0.7 million and $0.8 million of unamortized debt issuance costs as of June 30, 2024 and December 31, 2023, respectively.