Retirement Plans - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	$ (461)	$ (347)	$ (225)
Transition obligation	0	0	0
Total	(461)	$ (347)	$ (225)
Postretirement Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	0
Transition obligation	(60)
Total	$ (60)

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.

No definition available.

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

+ References

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 715
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Amount, before tax, of accumulated other comprehensive income (loss) for transition asset (obligation) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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