PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Fair Value Assumptions of Plan Assets) (Details) - USD ($) $ in Thousands	Mar. 26, 2017	Dec. 25, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	$ 101,180	$ 97,526
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	140	119
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	101,040	97,407
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	140	119
Cash and cash equivalents | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	140	119
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
Large U.S. equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	3,456	3,302
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
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	3,456	3,302
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
Large U.S. equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	24,785	24,547
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
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	24,785	24,547
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
Small/Mid U.S. equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	409	406
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
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	409	406
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
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	17,080	17,344
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
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	17,080	17,344
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
International equity funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	1,349	1,231
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
International equity funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	1,349	1,231
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
International equity funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	18,784	17,006
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
International equity funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	18,784	17,006
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
Fixed income funds | Pooled separate accounts
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	4,828	4,867
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
Fixed income funds | Pooled separate accounts | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	4,828	4,867
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
Fixed income funds | Common collective trusts funds
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	30,349	28,704
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
Fixed income funds | Common collective trusts funds | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Fair value of plan assets	30,349	28,704
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