RETIREMENT FUND AND PROFIT SHARING PLAN, SERP, Obligations and Funded Status (Details) - SERP [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Change in fair value of plan assets [Roll Forward]
Fair value of plan assets, beginning of period	$ 0	$ 0
Company contributions	325	240
Benefits paid	(325)	(240)
Fair value of plan assets, end of period	0	0
Change in benefit obligation [Roll Forward]
Benefit obligation, beginning of period	19,134	16,900
Service cost	732	700
Interest cost	664	673
Benefits paid	(325)	(240)
Plan amendments	39	198
Actuarial (gains) losses	(1,568)	903
Benefit obligation, end of period	18,676	19,134
Funded (unfunded) status of plan [Abstract]
Underfunded status, December 31	(18,676)	(19,134)
Other disclosures [Abstract]
Accumulated benefit obligation	16,500	16,100
Fair value of life insurance policies and marketable securities held in a rabbi trust	13,000	14,000
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	200
Expected employer contributions in next fiscal year	300
Expected future benefit payments [Abstract]
2019	379
2020	659
2021	679
2022	902
2023	941
2024 - 2028	5,409
Amounts recognized in accumulated other comprehensive loss, pretax [Abstract]
Prior service cost	918	1,135
Net loss	1,977	3,732
Total amounts recognized in accumulated other comprehensive loss	$ 2,895	$ 4,867

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