Composition of Certain Financial Statement Captions (Deferred Contract Costs) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Items Included in Consolidated Statement of Financial Condition [Abstract]
Deferred contract costs	$ 37,505,000		$ 37,928,000
Capitalized contract cost, amount capitalized during period	1,744,000	$ 3,519,000
Amortization of deferred contract costs	2,167,000	3,908,000
Accelerated amortization of deferred contract costs		$ 1,784,000
Capitalized contract cost impairment	$ 0