Acquisitions - Narrative (Details) $ in Thousands	1 Months Ended		3 Months Ended						12 Months Ended
	Oct. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) business	Sep. 30, 2021 USD ($) business	Jun. 30, 2021 USD ($) business	Mar. 31, 2021 USD ($) business	Dec. 31, 2020 USD ($) business	Jun. 30, 2020 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Acquisitions
Cash paid, net of cash acquired									$ 80,078	$ 21,801	$ 36,585
Acquisition-related costs									1,600	600
General and administrative expenses
Acquisitions
Acquisition-related costs									2,100	900
2021 Acquisitions
Acquisitions
Number of businesses acquired | business			8	3	2	3
Number of business' assets acquired | business				1		1
Aggregate purchase price			$ 53,100	$ 6,200	$ 21,000	$ 24,200			104,558
Cash paid, net of cash acquired			40,800	3,900	16,000	19,200			79,927
Issuance of Seller Notes at fair value			12,300	1,500	4,900	4,000			22,706
Additional consideration, net				$ 800	$ 100	$ 1,000			1,925
Operating right-of-use assets			8,900						8,900
Operating lease liabilities			$ 8,900						$ 8,900
2021 Acquisitions | Minimum
Acquisitions
Notes payable to share holders in quarterly installments period									2 years
2021 Acquisitions | Maximum
Acquisitions
Notes payable to share holders in quarterly installments period									5 years
2020 Acquisitions
Acquisitions
Number of businesses acquired | business							4
Aggregate purchase price							$ 7,100	$ 46,200		53,262
Cash paid, net of cash acquired							4,900	16,800		21,709
Issuance of Seller Notes at fair value							1,900	21,900		23,766
Additional consideration, net		$ 3,600					300	4,000		4,319
Operating right-of-use assets							5,500			5,500
Operating lease liabilities							$ 5,500			5,500
Deferred payment obligation at fair value								$ 3,500		$ 3,468
Repayments of debt	$ 18,100
Remaining liabilities payable	$ 3,800
Payment period of liabilities incurred								3 years
Payment period following acquisition								3 years
Consideration through settlement of amounts due from acquiree		$ 400
2020 Acquisitions | Minimum
Acquisitions
Notes payable to share holders in quarterly installments period										3 years
2020 Acquisitions | Maximum
Acquisitions
Notes payable to share holders in quarterly installments period										5 years