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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of accumulated other comprehensive (income) loss for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of net periodic benefit cost (credit) for defined benefit plan.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of cost for defined contribution plan.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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RETIREMENT FUND AND PROFIT SHARING PLAN (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Class A Common Stock [Member] \| UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	71,616
Class B Common Stock [Member] \| UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	141,652
401K Plan [Member] \| UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Compensation expense	$ 300	$ 300
Retirement Fund [Member] \| HONG KONG
Defined Contribution Plan Disclosure [Line Items]
Compensation expense	$ 100	100
Retirement Fund [Member] \| Class A Common Stock [Member] \| HONG KONG
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	3,323
Retirement Fund [Member] \| Class B Common Stock [Member] \| HONG KONG
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	17,342
SERP [Member]
Components of SERP expense [Abstract]
Service cost	$ 183	175
Interest cost	166	168
Net amortization	111	94
Net periodic benefit cost	460	$ 437
Amounts recognized in accumulated other comprehensive loss, pretax [Abstract]
Prior service cost	1,071		$ 1,135
Net loss	3,685		3,732
Total amounts recognized in accumulated other comprehensive loss	$ 4,756		$ 4,867