EMPLOYEE BENEFIT PLANS - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) plan	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of savings plan | plan	2
Provision for profit sharing contributions	$ 1,022	$ 592	$ 825
Provision for matching 401(k) savings plan contributions	$ 3,751	3,451	$ 3,153
Number of unfunded plans | plan	2
Deferred compensation liability	$ 3,581	1,982
Pension Plan | Chemogas Defined Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	950	$ 596
Estimated employer contributions to pension plans for 2021	$ 59