Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Income (Loss) Before Income Taxes	$ 2,387		$ 3,407		$ (11,950)	$ 4,485
Tax benefit (expense)	(1,635)		588		2,733	280
Net Income (Loss)	752	$ (9,969)	3,995	$ 770	(9,217)	4,765
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit plan adjustments – actuarial losses	(277)		(217)		(481)	(393)
Income (Loss) Before Income Taxes	409		(118)		(1,211)	(232)
Tax benefit (expense)	(92)		41		339	80
Net Income (Loss)	317		(77)		(872)	(152)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] \| Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Net investment gain (loss)	$ 686		$ 99		$ (730)	$ 161

Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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