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	Sep. 30, 2022	Dec. 31, 2021
Level 1 [Member]
Financial Assets:
Cash and Cash Equivalents	$ 473,066	$ 575,317
Certificates of Deposit, at Carrying Value	0	0
Receivables(1)	0	0
Contract Assets(2)	0	0
Receivable from Employees and Related Parties	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, at Carrying Value	138,701	141,218
Receivables(1)	359,246	436,749
Contract Assets(2)	33,919	25,986
Receivable from Employees and Related Parties	23,178	25,208
Financial Liabilities:
Accounts Payable and Accrued Expenses	33,088	31,633
Payable to Employees and Related Parties	36,461	58,876
Notes Payable	343,898	390,288
Level 3 [Member]
Financial Assets:
Cash and Cash Equivalents	0	0
Certificates of Deposit, at Carrying Value	0	0
Receivables(1)	0	0
Contract Assets(2)	0	0
Receivable from Employees and Related Parties	0	0
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	473,066	575,317
Certificates of Deposit, at Carrying Value	138,701	141,218
Receivables(1)	360,766	439,432
Contract Assets(2)	34,066	27,037
Receivable from Employees and Related Parties	23,178	25,208
Financial Liabilities:
Accounts Payable and Accrued Expenses	33,088	31,633
Payable to Employees and Related Parties	36,461	58,876
Notes Payable	369,300	376,243
Total [Member]
Financial Assets:
Cash and Cash Equivalents	473,066	575,317
Certificates of Deposit, at Carrying Value	138,701	141,218
Receivables(1)	359,246	436,749
Contract Assets(2)	33,919	25,986
Receivable from Employees and Related Parties	23,178	25,208
Financial Liabilities:
Accounts Payable and Accrued Expenses	33,088	31,633
Payable to Employees and Related Parties	36,461	58,876
Notes Payable	343,898	390,288
Equity Securities [Member] | Level 1 [Member]
Financial Assets:
Investments	0	0
Equity Securities [Member] | Level 2 [Member]
Financial Assets:
Investments	0	0
Equity Securities [Member] | Level 3 [Member]
Financial Assets:
Investments	557	676
Equity Securities [Member] | Carrying Amount [Member]
Financial Assets:
Investments	557	676
Equity Securities [Member] | Total [Member]
Financial Assets:
Investments	$ 557	$ 676