ACQUISITIONS - Assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 846,704	$ 786,504	$ 717,861
Total cash purchase price	119,188	146,098	$ 147,613
2022 Acquisitions
Business Acquisition [Line Items]
Total cash purchase price	116,000
Acquisitions
Business Acquisition [Line Items]
Accounts receivable, net	3,736	3,072
Materials and supplies	529	891
Equipment and property	6,741	8,184
Goodwill	64,997	69,555
Current liabilities	(4,853)	(6,483)
Other assets and liabilities, net	(1,948)	288
Total consideration paid	126,226	160,614
Less: Acquisition holdback liabilities	(10,178)	(14,516)
Total cash purchase price	116,048	146,098
Acquisitions | Customer Contracts
Business Acquisition [Line Items]
Intangible assets	49,871	80,239
Acquisitions | Trademarks & Tradenames
Business Acquisition [Line Items]
Intangible assets	5,615	1,200
Acquisitions | Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets	$ 1,538	$ 3,668