Corporate Borrowings - Indebtedness Outstanding (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 01, 2023	Dec. 31, 2022	Nov. 16, 2021
Debt Instrument [Line Items]
Total indebtedness outstanding	$ 323,450		$ 236,450
Less unamortized loan fees	(6,773)		(6,115)
Total indebtedness outstanding, net	316,677		230,335
Less current maturities of long-term debt	(6,400)		(5,600)
Long-term debt	310,277		224,735
Credit Agreement - Revolver, 6.42% (variable rate) due 2026 | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Total indebtedness outstanding	$ 91,000	$ 105,000	0
Credit agreement, interest rate	6.42%
Convertible Senior Notes, 1.88% (fixed rate) due 2041 | Convertible Debt
Debt Instrument [Line Items]
Total indebtedness outstanding	$ 201,250		201,250
Stated interest rate	1.88%			1.88%
Series A Senior Secured Notes, 3.53% (fixed rate) due 2027 | Secured Debt
Debt Instrument [Line Items]
Total indebtedness outstanding	$ 12,800		15,200
Stated interest rate	3.53%
Senior Secured Notes, 3.80% (fixed rate) due 2029 | Secured Debt
Debt Instrument [Line Items]
Total indebtedness outstanding	$ 18,400		$ 20,000
Stated interest rate	3.80%