DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES - Narrative (Details) $ in Thousands					3 Months Ended	12 Months Ended
	Dec. 28, 2018 USD ($) swap	Aug. 07, 2018 USD ($)	Nov. 29, 2017 USD ($) swap	Aug. 03, 2017 USD ($) swap	Mar. 18, 2019 USD ($) swap	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Aug. 13, 2015 USD ($) swap
Derivative [Line Items]
Number of swaps terminated | swap	1		4	3
Notional amount of terminated swaps	$ 50,000		$ 150,000	$ 65,000
Amounts reclassified to interest expense upon interest rate hedge termination		$ 8	926			$ 1,552	$ 0	$ 0
Proceeds from termination payments, net of fees	684						1,011
Payment of derivative fees and accrued interest							38
Increase in interest expense related to change in fair value of interest rate swaps						$ 1,728	$ 0	$ 0
Interest rate swap
Derivative [Line Items]
Number of interest rate swaps | swap									10
Derivative, notional amount									$ 385,000
Unsecured term facility entered into in May 2015
Derivative [Line Items]
Repayments of debt			$ 150,000	$ 65,000
Revolving Credit Facility | Line of Credit
Derivative [Line Items]
Repayments of debt	$ 40,000
Subsequent event
Derivative [Line Items]
Number of swaps terminated | swap					2
Notional amount of terminated swaps					$ 120,000
Amounts reclassified to interest expense upon interest rate hedge termination					1,580
Proceeds from termination payments, net of fees					1,302
Subsequent event | Interest rate swap
Derivative [Line Items]
Derivative, fair value					1,421
Subsequent event | Revolving Credit Facility | Line of Credit
Derivative [Line Items]
Repayments of debt					$ 130,000