Other Comprehensive Income and Loss - Changes in Components of Accumulated Other Comprehensive Income and Loss (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Changes in the components of accumulated other comprehensive loss, net of taxes
Balances at beginning of period	$ (243,919)	$ (238,838)	$ (243,890)	$ (235,079)
Other comprehensive income, net of taxes	93	(119)	195	(609)
Balances at end of period	(244,027)	(241,772)	(244,027)	(241,772)
Accumulated Other Comprehensive Loss
Changes in the components of accumulated other comprehensive loss, net of taxes
Balances at beginning of period	7,770	7,319	7,668	7,809
Other comprehensive income, net of taxes	93	(119)	195	(609)
Net current period other comprehensive (gain) loss	93	(119)	195	(609)
Balances at end of period	7,863	7,200	7,863	7,200
Other comprehensive income, net of taxes
Changes in the components of accumulated other comprehensive loss, net of taxes
Other comprehensive income, net of taxes	(19)	(151)	(26)	(641)
Unfunded Pension Liability
Changes in the components of accumulated other comprehensive loss, net of taxes
Balances at beginning of period	8,178	7,721	8,178	7,721
Balances at end of period	8,178	7,721	8,178	7,721
Amount Reclassified from Other Comprehensive Income
Changes in the components of accumulated other comprehensive loss, net of taxes
Other comprehensive income, net of taxes	112	32	221	32
Amounts reclassified from accumulated other comprehensive income, net of taxes	(112)	(32)	(221)	(32)
Unrealized (Gain)/Loss on Securities
Changes in the components of accumulated other comprehensive loss, net of taxes
Balances at beginning of period	(408)	(402)	(510)	88
Other comprehensive income, net of taxes	(19)	(151)	(26)	(641)
Net current period other comprehensive (gain) loss		(119)	195	(609)
Balances at end of period	$ (315)	$ (521)	$ (315)	$ (521)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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