PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Fair Value Assumptions of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 29, 2019	Dec. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	$ 294,589	$ 102,414
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	11,582	110
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	283,007	102,304
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	11,582	110
Cash and cash equivalents | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	11,582	110
Cash and cash equivalents | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Large U.S. equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	3,071	2,491
Union plan | Large U.S. equity funds | Pooled separate accounts | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Large U.S. equity funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	3,071	2,491
Union plan | Large U.S. equity funds | Pooled separate accounts | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Small/Mid U.S. equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	372	292
Union plan | Small/Mid U.S. equity funds | Pooled separate accounts | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Small/Mid U.S. equity funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	372	292
Union plan | Small/Mid U.S. equity funds | Pooled separate accounts | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | International equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	1,878	1,489
Union plan | International equity funds | Pooled separate accounts | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | International equity funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	1,878	1,489
Union plan | International equity funds | Pooled separate accounts | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Fixed income funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	4,452	4,763
Union plan | Fixed income funds | Pooled separate accounts | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
Union plan | Fixed income funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	4,452	4,763
Union plan | Fixed income funds | Pooled separate accounts | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Large U.S. equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	20,378	17,351
GK Pension Plan | Large U.S. equity funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Large U.S. equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	20,378	17,351
GK Pension Plan | Large U.S. equity funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Small/Mid U.S. equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	12,495	5,880
GK Pension Plan | Small/Mid U.S. equity funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Small/Mid U.S. equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	12,495	5,880
GK Pension Plan | Small/Mid U.S. equity funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | International equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	25,149	22,516
GK Pension Plan | International equity funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | International equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	25,149	22,516
GK Pension Plan | International equity funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Fixed income funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	35,627	42,217
GK Pension Plan | Fixed income funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Fixed income funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	35,627	42,217
GK Pension Plan | Fixed income funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Real estate | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	5,613	5,305
GK Pension Plan | Real estate | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
GK Pension Plan | Real estate | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	5,613	5,305
GK Pension Plan | Real estate | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | Large U.S. equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	17,756	0
U.K. Plans | Large U.S. equity funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | Large U.S. equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	17,756	0
U.K. Plans | Large U.S. equity funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | International equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	102,494	0
U.K. Plans | International equity funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | International equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	102,494	0
U.K. Plans | International equity funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | Fixed income funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	53,722	0
U.K. Plans | Fixed income funds | Common collective trusts funds | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	0	0
U.K. Plans | Fixed income funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	53,722	0
U.K. Plans | Fixed income funds | Common collective trusts funds | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	$ 0	$ 0