ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Statement [Abstract]
Net sales	$ 297,602	$ 229,125	$ 231,654	$ 155,353	$ 241,179	$ 196,109	$ 206,288	$ 135,257	$ 913,734	$ 778,833	$ 639,239
Cost of goods sold									438,420	395,705	344,638
Gross profit	162,334	120,076	116,277	76,627	127,828	97,541	100,570	57,189	475,314	383,128	294,601
Selling, general, and administrative expenses									385,543	280,972	230,634
Operating income									89,771	102,156	63,967
Interest expense									(21,779)	(31,280)	(32,607)
Other income									(734)	(1,261)	699
Income before income taxes									67,258	69,615	32,059
Income tax expense									(16,824)	(11,852)	(16,658)
Net income	4,742	$ 21,302	$ 22,223	$ 2,167	25,169	$ 17,030	$ 18,825	$ (3,261)	50,434	57,763	$ 15,401
ASSETS
Accounts receivable, net	82,688				59,328				82,688	59,328
Inventory	185,700				145,423				185,700	145,423
Prepaid expenses and other current assets	19,644				12,211				19,644	12,211
Deferred charges and other assets	2,389				1,014				2,389	1,014
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued expenses and other current liabilities	42,088				53,022				42,088	53,022
Taxes payable	3,329				6,390				3,329	6,390
Accumulated deficit	(189,545)				$ (240,104)				(189,545)	$ (240,104)
Impact of Adoption | No. 2014-09
Income Statement [Abstract]
Net sales									(2,091)
Cost of goods sold									(529)
Gross profit									(1,562)
Selling, general, and administrative expenses									451
Operating income									(2,013)
Income before income taxes									(2,013)
Income tax expense									494
Net income									(1,519)
ASSETS
Accounts receivable, net	(3,550)								(3,550)
Inventory	876								876
Prepaid expenses and other current assets	(197)								(197)
Deferred charges and other assets	2								2
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued expenses and other current liabilities	(850)								(850)
Taxes payable	0								0
Accumulated deficit	(2,019)								(2,019)
Balances without Adoption of ASC 606
Income Statement [Abstract]
Net sales									911,643
Cost of goods sold									437,891
Gross profit									473,752
Selling, general, and administrative expenses									385,994
Operating income									87,758
Interest expense									(21,779)
Other income									(734)
Income before income taxes									65,245
Income tax expense									(16,330)
Net income									48,915
ASSETS
Accounts receivable, net	79,138								79,138
Inventory	186,576								186,576
Prepaid expenses and other current assets	19,447								19,447
Deferred charges and other assets	2,391								2,391
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued expenses and other current liabilities	41,238								41,238
Taxes payable	3,329								3,329
Accumulated deficit	$ (191,564)								$ (191,564)