Investments in Securities and Fair Value Investments in Securities (Schedule of Cost-method Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair​Value​Assets​Measured​On​Nonrecurring​Basis​Reconciliation​Calculation​Roll​Forward [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	$ 9,300	$ 8,915
Notes Receivable, Fair Value Disclosure	2,201	1,921
Other Assets, Fair Value Disclosure	11,501	10,836
Level 1
Fair​Value​Assets​Measured​On​Nonrecurring​Basis​Reconciliation​Calculation​Roll​Forward [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Notes Receivable, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Level 2
Fair​Value​Assets​Measured​On​Nonrecurring​Basis​Reconciliation​Calculation​Roll​Forward [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Notes Receivable, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Level 3
Fair​Value​Assets​Measured​On​Nonrecurring​Basis​Reconciliation​Calculation​Roll​Forward [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	9,300	8,915
Notes Receivable, Fair Value Disclosure	2,201	1,921
Other Assets, Fair Value Disclosure	$ 11,501	$ 10,836