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	Mar. 31, 2024	Dec. 31, 2023
Level 1 [Member]
Financial Assets:
Cash and Cash Equivalents	$ 560,100	$ 588,321
Certificates of Deposit	0	0
Receivables(1)	0	0
Contract Assets(2)	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	48,001	54,856
Receivables(1)	414,158	461,682
Contract Assets(2)	36,650	90,876
Closely-held Equity Securities	0	0
Financial Liabilities:
Accounts Payable and Accrued Expenses	29,520	25,989
Payable to Employees and Related Parties	63,841	45,838
Notes Payable	353,518	360,252
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
Closely-held Equity Securities	631	636
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	560,100	588,321
Certificates of Deposit	48,001	54,856
Receivables(1)	416,997	465,295
Contract Assets(2)	37,273	91,246
Closely-held Equity Securities	631	636
Financial Liabilities:
Accounts Payable and Accrued Expenses	29,520	25,989
Payable to Employees and Related Parties	63,841	45,838
Notes Payable	373,756	373,885
Total [Member]
Financial Assets:
Cash and Cash Equivalents	560,100	588,321
Certificates of Deposit	48,001	54,856
Receivables(1)	414,158	461,682
Contract Assets(2)	36,650	90,876
Closely-held Equity Securities	631	636
Financial Liabilities:
Accounts Payable and Accrued Expenses	29,520	25,989
Payable to Employees and Related Parties	63,841	45,838
Notes Payable	$ 353,518	$ 360,252