Retirement Fund and Profit Sharing Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Contribution Plan Disclosure [Line Items]
Employer match of the first 1% of compensation contributed by participants (in hundredths)	100.00%
Percentage of participant contribution under condition one (in hundredths)	1.00%
Employer match of the next 5% compensation contributed by participants (in hundredths)	50.00%
Percentage of employee deferrals under condition two (in hundredth)	5.00%
Maximum employee deferral contribution under Asia Retirement Fund (in hundredths)	5.00%
Minimum employer matching contribution (in hundredths)	5.00%
Employer matching contribution (in hundredths)	7.00%
Amounts recognized in accumulated other comprehensive loss, pretax:
Total amounts recognized in accumulated other comprehensive loss	$ 3,026,000	$ 1,541,000	$ 2,610,000
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension expense	1,300,000	1,300,000	1,100,000
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 (in hundredths)	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
Minimum number of monthly payments entitled to beneficiary in case participant dies prior to receiving one hundred twenty monthly payments	60 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 (in hundredths)	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 (in hundredths)	50.00%
Period for which beneficiary will receive fifty percent annual base salary	4 years
Components of SERP expense [Abstract]
Service Cost	542,000	556,000	438,000
Interest Cost	541,000	448,000	417,000
Net amortization	182,000	307,000	230,000
Net periodic benefit cost	1,265,000	1,311,000	1,085,000
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	16,000	0
Benefits paid	(16,000)	0
Fair value of plan assets, end of period	0	0	0
Benefit obligation January 1	10,830,000	11,045,000
Service cost	542,000	556,000	438,000
Interest cost	541,000	448,000	417,000
Plan amendments	0	502,000
Benefits paid	(16,000)	0
Actuarial (gains) losses	2,308,000	(1,721,000)
Benefit obligation, December 31	14,205,000	10,830,000	11,045,000
Underfunded status, December 31	(14,205,000)	(10,830,000)
Accumulated benefit obligation	12,100,000	9,200,000
Fair value of life insurance policies and marketable securities held in a rabbi trust	12,300,000	11,900,000
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	400,000
Expected employer contributions in next fiscal year	100,000
Expected future benefit payments [Abstract]
2015	63,000
2016	267,000
2017	267,000
2018	267,000
2019	477,000
2020 - 2024	3,876,000
Amounts recognized in accumulated other comprehensive loss, pretax:
Prior service cost	1,048,000	1,230,000
Net loss	3,302,000	1,004,000
Total amounts recognized in accumulated other comprehensive loss	4,350,000	2,234,000
Net periodic benefit cost
Discount rate (in hundredths)	5.00%	4.00%	4.50%
Rate of compensation increase (in hundredths)	3.00%	3.00%	3.00%
Benefit obligation
Discount rate (in hundredths)	4.00%	5.00%	4.00%
Rate of compensation increase (in hundredths)	3.00%	3.00%	3.00%
Common Class A [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	14,253
Common Class B [Member]
Defined Contribution Plan Disclosure [Line Items]
Shares owned by plan (in shares)	178,239
Retirement Fund [Member]
Defined Contribution Plan Disclosure [Line Items]
Compensation expenses	300,000	300,000	300,000
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	$ 800,000	$ 400,000	$ 500,000