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SHAREHOLDERS’ EQUITY (Details)					3 Months Ended		12 Months Ended
	Dec. 27, 2019 shares	Mar. 28, 2008 shares	Mar. 01, 2008 shares	Jun. 30, 2006 shares	Jan. 02, 2009 shares	Jun. 27, 2008 shares	Dec. 27, 2019 USD ($) plan shares	Dec. 28, 2018 USD ($) shares	Dec. 29, 2017 USD ($) shares	Dec. 30, 2016 shares	Jan. 01, 2016 shares	Dec. 28, 2012 shares	Dec. 31, 2010 shares	Jun. 30, 2008 shares	Mar. 31, 2008 shares
Equity plans
Number of share-based compensation plans | plan							2
2006 Plan
Equity plans
Granted (in shares)							0
Number of shares of common stock reserved for issuance				300,000
2008 Plan
Equity plans
Number of shares of common stock reserved for issuance	418,000						418,000								450,000
Shares available for grant under 2008 Plan from 2006 Plan														70,333
Number of additional shares authorized							955,000		875,000	500,000		500,000	350,000
Stock options
Equity plans
Compensation expense recognized | $							$ 12,112,000
Granted (in shares)								158,000	199,000
Options outstanding (in shares)	1,124,000						1,124,000	1,252,000	1,207,000	1,311,000
Stock options | 2006 Plan
Equity plans
Options outstanding (in shares)	0						0
Stock options | 2008 Plan
Equity plans
Maximum number of shares a participant may be granted in options to purchase during fiscal year							300,000
Incentive stock options | 2008 Plan
Equity plans
Outstanding options granted, net of forfeitures, expirations and exercises (in shares)		509,000	509,000		509,000	509,000	509,000	509,000	509,000	509,000	509,000	509,000	509,000
Non-statutory/Nonqualified stock options | 2006 Plan | Maximum
Equity plans
Expiration period from date of grant				10 years
Non-statutory/Nonqualified stock options | 2008 Plan
Equity plans
Outstanding options granted, net of forfeitures, expirations and exercises (in shares)	598,000		598,000
Non-statutory/Nonqualified stock options | 2008 Plan | Maximum
Equity plans
Expiration period from date of grant							10 years
Restricted stock
Equity plans
Compensation expense recognized | $								$ 6,262,000
Restricted stock | 2008 Plan
Equity plans
Shares granted	101,000		101,000
Performance Shares
Equity plans
Compensation expense recognized | $									$ 2,774,000
Performance Shares | 2008 Plan
Equity plans
Shares granted	326,000		326,000

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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