Retirement-related Benefits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Total fair value of assets	$ 1,027	$ 1,066
Equity Mutual Funds [Member]
Total fair value of assets	701	740
Fixed Income - Corporate Bonds [Member]
Total fair value of assets	$ 326	$ 326

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Name:	us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant