LONG-TERM OBLIGATIONS - Narrative (Details)		3 Months Ended	5 Months Ended	12 Months Ended			21 Months Ended
	Aug. 28, 2015 USD ($)	Sep. 30, 2015 USD ($)	Aug. 19, 2020 USD ($)	Dec. 31, 2017 USD ($) installment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2020 installment	Mar. 31, 2018 installment
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 300,000,000
Principal payments of long-term obligations				$ 5,319,000	$ 5,000,000	$ 103,000,000
Total leverage ratio				0.9
Fixed charge coverage ratio				4.4
Write-off of deferred debt issuance cost		$ 2,500,000
Deferred debt issuance cost						$ 2,400,000
Principal amount				$ 90,700,000	95,700,000
Swing Line Loan [Member]
Debt Instrument [Line Items]
Amount of revolving credit facility	25,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Amount of revolving credit facility	50,000,000
Credit Agreement [Member]
Debt Instrument [Line Items]
Additional interest rate over Federal Funds rate (percent)				0.50%
Additional interest rate over Eurodollar Rate (percent)				1.00%
Percentage of consolidated revenue and adjusted EBITDA that guarantor wholly-owned subsidiaries represent				95.00%
Percentage of adjusted EBITDA that guarantor subsidiaries represent				70.00%
Credit Agreement [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Description of variable rate basis				Fluctuating rate per annum equal to the highest of (a) the federal funds rate plus 0.50% per annum, (b) the prime rate of interest established by the Administrative Agent, and (c) the Eurodollar Rate for an interest period of one month plus 1% per annum.
Basis spread on variable rate (percent)				1.00%
Credit Agreement [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Description of variable rate basis				Rate at which Eurodollar deposits in the London interbank market for an interest period of one, two, three or six months
Basis spread on variable rate (percent)				2.00%
Promissory Notes [Member]
Debt Instrument [Line Items]
Principal amount				$ 700,000	$ 700,000
Promissory Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate (percent)				2.60%
Promissory Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate (percent)				2.90%
100 Million Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	100,000,000.0
Principal amount	100,000,000			$ 100,000,000
Maturity date				Aug. 28, 2020
Number of quarterly installments | installment				10
Frequency of periodic payment				quarterly
Weighted-average interest rate for five year Term Loan (percent)				3.10%	2.50%
Principal amount				$ 90,000,000	$ 95,000,000
100 Million Term Loan [Member] | Term Loan [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (percent)				3.57%
100 Million Term Loan [Member] | Term Loan [Member] | Forecast [Member]
Debt Instrument [Line Items]
Number of quarterly installments | installment								2	8
Periodic principal payment			$ 3,100,000				$ 2,500,000
200 Million Revolving Credit Facility [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal amount	200,000,000.0			$ 200,000,000
Amount of revolving credit facility	200,000,000.0
Credit facility, maximum additional borrowing capacity	150,000,000
Maturity date				Aug. 28, 2020
Weighted-average interest rate for five year Term Loan (percent)					3.50%
Availability under the revolving credit facility				$ 167,300,000
Outstanding letters of credit				32,700,000
Principal amount				$ 0	$ 0
October 2012 Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Principal amount	27,000,000
Principal payments of long-term obligations	27,000,000
Second Lien Credit Agreement [Member]
Debt Instrument [Line Items]
Call premium payment	700,000
Second Lien Credit Agreement [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Principal amount	70,000,000
Principal payments of long-term obligations	$ 70,000,000