RETIREMENT FUND AND PROFIT SHARING PLAN (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Employer match of the first 1% of compensation contributed by participants	100.00%
Percentage of participant contribution under condition one	1.00%
Employer match of the next 5% compensation contributed by participants, percentage	50.00%
Percentage of employee deferrals under condition two	5.00%
Employer matching contribution, percentage	7.00%
Minimum [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percentage	5.00%
Maximum [Member]
Defined Contribution Plan Disclosure [Line Items]
Employee matching contribution per participant under prior plan	5.00%
Common Class A [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	13,637
Common Class B [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	159,688
Retirement Fund [Member]
Defined Contribution Plan Disclosure [Line Items]
Compensation expenses	$ 300	$ 300	$ 300
Retirement Fund [Member] | Common Class A [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	3,323
Retirement Fund [Member] | Common Class B [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	17,342
401K Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Compensation expenses	$ 1,100	1,200	800
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension expense	$ 1,600	1,500	1,300
Normal retirement age	65 years
Number of years of service	20 years
Number of years of plan participation	5 years
Percentage of average base compensation payable as normal retirement benefit under the plan	40.00%
Early retirement age	55 years
Number of consecutive calendar years of plan participation to calculate average base compensation	20 years
Number of monthly payments under the death benefit of the plan	120 months
Period for which beneficiary is entitled to receive benefit	shorter of (i) the time necessary to complete 120 monthly payments or (ii) 60 months
Percentage of participant's annual base salary received by beneficiary for one year from date of death	100.00%
Period for which beneficiary will receive hundred percent annual base salary	1 year
Percentage of participant's annual base salary received by beneficiary for years two through five following date of death	50.00%
Period for which beneficiary will receive fifty percent annual base salary	4 years
Components of SERP expense [Abstract]
Service Cost	$ 593	552	542
Interest Cost	659	567	541
Net amortization	391	366	182
Net periodic benefit cost	1,643	1,485	1,265
Summary of information about changes in plan assets, benefit obligation, and the funded status [Abstract]
Fair value of plan assets, beginning of period	0	0
Company contributions	129	85
Benefits paid	(129)	(85)
Fair value of plan assets, end of period	0	0	0
Benefit obligation January 1	15,576	14,205
Service cost	593	552	542
Interest cost	659	567	541
Benefits paid	(129)	(85)
Plan amendments	487	0
Actuarial (gains) losses	(286)	337
Benefit obligation, December 31	16,900	15,576	$ 14,205
Underfunded status, December 31	(16,900)	(15,576)
Accumulated benefit obligation	13,800	12,700
Fair value of life insurance policies and marketable securities held in a rabbi trust	12,700	12,200
Estimated net loss and prior service cost that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next fiscal year	400
Expected employer contributions in next fiscal year	100
Expected future benefit payments [Abstract]
2017	129
2018	288
2019	543
2020	658
2021	658
2022 - 2026	5,160
Amounts recognized in accumulated other comprehensive loss, pretax [Abstract]
Prior service cost	1,172	866
Net loss	2,970	3,465
Total amounts recognized in accumulated other comprehensive loss	$ 4,142	$ 4,331
Net periodic benefit cost [Abstract]
Discount rate	4.25%	4.00%	5.00%
Rate of compensation increase	3.00%	3.00%	3.00%
Benefit obligation [Abstract]
Discount rate	4.00%	4.25%	4.00%
Rate of compensation increase	3.00%	3.00%	3.00%
SERP [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of monthly payments entitled to beneficiary in case participant dies prior to receiving one hundred twenty monthly payments	60 months