INVESTMENTS IN SECURITIES (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains recognized on available-for-sale securities	$ 400,000	$ 900,000
Gross realized losses recognized on available-for-sale securities	6,500	83,400
Fixed income securities
Schedule of Available-for-sale Securities [Line Items]
Cost	330,456,000	140,480,000
Fair Value	330,456,000	140,480,000
Other
Schedule of Available-for-sale Securities [Line Items]
Cost	942,000	61,000
Fair Value	$ 942,000	$ 61,000