EMPLOYEE BENEFIT PLANS - Additional Information (Details) $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 28, 2019 plan	Oct. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) hour	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to multiemployer annuity fund				$ 3,412	$ 4,284	$ 3,285
Number of defined benefit plans acquired | plan	2
Non-current liabilities				$ (8,700)
Maximum percentage of employees income available for contribution				100.00%
Employer contribution expense				$ 1,600	1,000	900
Dover Downs Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Eligibility hours worked per year | hour				1,000
Expected return on plan assets				7.50%
Plan assets, target allocation				100.00%
Minimum required pension contributions				$ 500
Expected employer contributions				$ 800
Dover Downs Pension Plan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation				60.00%
Dover Downs Pension Plan | Equity Securities | Passively Managed
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation				50.00%
Dover Downs Pension Plan | Equity Securities | Actively Managed
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation				50.00%
Dover Downs Pension Plan | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation				40.00%
Excess Plan
Defined Benefit Plan Disclosure [Line Items]
Settlement payment			$ 500
New England Teamsters Pension Fund | New England Teamsters And Trucking Industry Pension Fund
Defined Benefit Plan Disclosure [Line Items]
Advertising, general and administrative expense		$ 3,700			3,700
Certain Bargaining Agreements
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to multiemployer annuity fund				$ 2,600	$ 2,700	$ 2,400