STOCK-BASED COMPENSATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015	Jul. 20, 2016	Jan. 02, 2016
Total Restricted Shares
Balance, at beginning of period			4,538,684	4,104,722
Granted			224,378	286,020
Forfeited			(98,543)
Repurchased			(243,839)
Balance, at end of period	4,420,680	4,390,742	4,420,680	4,390,742
Vested Restricted Shares
Balance vested, beginning of period			2,913,207	1,857,157
Granted, vested			62,616	279,457
Repurchased, vested			(243,839)
Balance vested, end of period	2,731,984	2,136,614	2,731,984	2,136,614
Unvested shares at end of period	1,688,696	2,254,128	1,688,696	2,254,128
Shares available for grant	986,210	1,062,646	986,210	1,062,646
Weighted average grant date fair value, Total restricted shares
Balance, beginning of period (per share)			$ 1.99	$ 1.51
Granted (per share)			10.66	1.52
Forfeited (per share)			1.01
Repurchased (per share)			0.89
Balance, end of period (per share)	$ 2.49	$ 1.51	2.49	1.51
Vested Restricted Shares (per share)
Balance, beginning of period (per share)			1.72	1.85
Granted (per share)			1.52	2.53
Repurchased (per share)			0.89
Balance, end of period (per share)	1.76	1.94	1.76	1.94
Unvested shares at end of period (price per share)	$ 3.67	$ 1.10	$ 3.67	$ 1.10
Share-based compensation narrative disclosures
Redemption of stock			$ 1,577
Liability for repurchase of stock	$ 19,384		19,384			$ 17,393
Restricted Shares
Share-based compensation narrative disclosures
Redemption of stock		$ 0	$ 1,577
Fair value, per share	$ 17.65		$ 17.65			$ 10.24
Restricted Shares | Selling, general and administrative expenses
Share-based compensation narrative disclosures
Compensation expense	$ 9,114	$ 6,665	$ 11,853	$ 7,217
Restricted Shares | Minimum
Equity Incentive Plan
Vesting period			3 years
Restricted Shares | Maximum
Equity Incentive Plan
Vesting period			4 years
Equity Incentive Plan
Equity Incentive Plan
Authorized shares					16,562,730
Share-based compensation narrative disclosures
Unrecognized compensation expense	$ 11,527		$ 11,527
Weighted average period for recognition of unrecognized compensation			1 year 7 months 13 days
Call right expiration, percentage of stock offered in public offering	25.00%		25.00%