Fair Value Measurements - Carrying Amount and Estimated Fair Value of Financial Instrument Assets and Liabilities which are Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Level 1 [Member]
Financial Assets:
Cash and Cash Equivalents	$ 655,461	$ 575,317
Certificates of Deposit	0	0
Receivables(1)	0	0
Contract Assets(2)	0	0
Receivable from Employees and Related Parties	0	0
Closely-held Equity Securities	0	0
Financial Liabilities:
Accounts Payable and Accrued Expenses	0	0
Payable to Employees and Related Parties	0	0
Notes Payable	0	0
Level 2 [Member]
Financial Assets:
Cash and Cash Equivalents	0	0
Certificates of Deposit	122,890	141,218
Receivables(1)	447,051	436,749
Contract Assets(2)	117,701	25,986
Receivable from Employees and Related Parties	21,914	25,208
Closely-held Equity Securities	0	0
Financial Liabilities:
Accounts Payable and Accrued Expenses	28,807	31,633
Payable to Employees and Related Parties	41,235	58,876
Notes Payable	349,955	390,288
Level 3 [Member]
Financial Assets:
Cash and Cash Equivalents	0	0
Certificates of Deposit	0	0
Receivables(1)	0	0
Contract Assets(2)	0	0
Receivable from Employees and Related Parties	0	0
Closely-held Equity Securities	604	676
Financial Liabilities:
Accounts Payable and Accrued Expenses	0	0
Payable to Employees and Related Parties	0	0
Notes Payable	0	0
Carrying Amount [Member]
Financial Assets:
Cash and Cash Equivalents	655,461	575,317
Certificates of Deposit	122,890	141,218
Receivables(1)	449,270	439,432
Contract Assets(2)	118,496	27,037
Receivable from Employees and Related Parties	21,914	25,208
Closely-held Equity Securities	604	676
Financial Liabilities:
Accounts Payable and Accrued Expenses	28,807	31,633
Payable to Employees and Related Parties	41,235	58,876
Notes Payable	371,774	376,243
Total [Member]
Financial Assets:
Cash and Cash Equivalents	655,461	575,317
Certificates of Deposit	122,890	141,218
Receivables(1)	447,051	436,749
Contract Assets(2)	117,701	25,986
Receivable from Employees and Related Parties	21,914	25,208
Closely-held Equity Securities	604	676
Financial Liabilities:
Accounts Payable and Accrued Expenses	28,807	31,633
Payable to Employees and Related Parties	41,235	58,876
Notes Payable	$ 349,955	$ 390,288