COMPONENTS OF PENSION PLAN NET PERIODIC BENEFIT COSTS (Details) - USD ($) $ in Thousands		3 Months Ended
	Apr. 17, 2017	Mar. 31, 2017	Mar. 31, 2016
Pension Plan
Components of net periodic benefit cost:
Service cost			$ 598
Interest cost		$ 1,135	1,132
Expected return on plan assets		(1,252)	(1,287)
Amortization of prior service cost (1)		47
Amortization of net loss		773	789
Net periodic benefit cost		703	$ 1,232
2016 plan year
Components of net periodic benefit cost:
Employer contribution		$ 700
2017 plan year
Components of net periodic benefit cost:
Employer contribution	$ 600