Fair Value of Financial Instruments - Other Investments - Other Equity Method Investments - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		33 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, net investment	$ 325,000			$ 325,000		$ 325,000	$ 306,000
Equity method investments, equity contributions	100			300
Equity method investments, equity in earnings (losses)	6,787		$ 6,059	23,434	$ 19,423
Subcontracting Arrangements | Related Party
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Operating costs and expenses	1,700		400	2,900	900
Accounts payable	600			600		600	300
Accounts receivable, after allowance for credit loss	59,100			59,100		59,100	42,000
Telecommunications Equity Method Investees
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, net investment	21,000			21,000		21,000	21,000
Equity method investments, equity contributions	0		0	0	1,100
Equity method investments, equity in earnings (losses)	(700)		400	300	(500)
Payments for advance to affiliate	200		2,000	700	2,000
Telecommunications Equity Method Investees | Subcontracting Arrangements | Related Party
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Operating costs and expenses	400		2,600	1,300	5,100
Accounts payable	200			200		200	200
Telecommunications Equity Method Investees | Employee Leasing and Advanced Receivable Arrangement | Related Party
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Accounts receivable, after allowance for credit loss	4,200			4,200		4,200	3,800
FM Tech
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, net investment	$ 18,000			$ 18,000		$ 18,000	18,000
Equity method investments, ownership percentage	50.00%			50.00%		50.00%
Certain Entities, Each Accounted for Using Equity Method Investments
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, net investment	$ 3,000			$ 3,000		$ 3,000	$ 3,000
Equity method investments, equity in earnings (losses)	$ (200)		(100)	$ (100)	(400)
Equity method investments, ownership percentage	49.00%			49.00%		49.00%	49.00%
Line of credit, amount drawn	$ 3,000			$ 3,000		$ 3,000	$ 4,500
Certain Entities, Each Accounted for Using Equity Method Investments | Related Party
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Operating costs and expenses	200		$ 800	800	5,800
Certain Entities, Each Accounted for Using Equity Method Investments | Other Current Assets
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Line of credit, amount drawn	$ 0			0		0	$ 600
Confluence
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity method investments, equity contributions				200	200	$ 2,100
Equity method investments, equity in earnings (losses)				$ (100)	$ (300)
Equity method investments, ownership percentage	75.00%			75.00%		75.00%
Financing commitments (up to)								$ 2,500
AVCT | Corporate
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity investments written off		$ 200