Defined Benefit Plan, Diversification, Number of Investements

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Defined Benefit Plan, Diversification, Percentage

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Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.

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- Definition

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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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Pension and Other Postretirement Plans (Plan Assets) (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) investment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Defined Benefit Pension Plans
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 16,169,000	$ 19,312,000	$ 18,279,000
Plan assets	$ 0	$ 0
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	100.00%	100.00%	100.00%
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage pension assets not invested in cash or U.S. Government agencies (in percentage)	99.00%
Number of different investments \| investment	208
Acceptable range for each asset class (in percentage)	2.60%
Defined Benefit Pension Plans \| Level 1
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 10,311,000	$ 12,941,000
Defined Benefit Pension Plans \| Level 2
Pension plan assets within the fair value hierachy
Fair value of plan assets	5,858,000	6,371,000
Defined Benefit Pension Plans \| Level 3
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Defined Benefit Pension Plans \| Cash and cash equivalents
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 209,000	$ 662,000
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	1.00%	3.00%	7.00%
Defined Benefit Pension Plans \| Cash and cash equivalents \| Level 1
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 209,000	$ 662,000
Defined Benefit Pension Plans \| Cash and cash equivalents \| Level 2
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Defined Benefit Pension Plans \| Cash and cash equivalents \| Level 3
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 0	$ 0
Defined Benefit Pension Plans \| Equity securities
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	63.00%	64.00%	62.00%
Defined Benefit Pension Plans \| Domestic
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 9,909,000	$ 11,885,000
Defined Benefit Pension Plans \| Domestic \| Level 1
Pension plan assets within the fair value hierachy
Fair value of plan assets	9,909,000	11,885,000
Defined Benefit Pension Plans \| Domestic \| Level 2
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Defined Benefit Pension Plans \| Domestic \| Level 3
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Defined Benefit Pension Plans \| International
Pension plan assets within the fair value hierachy
Fair value of plan assets	193,000	394,000
Defined Benefit Pension Plans \| International \| Level 1
Pension plan assets within the fair value hierachy
Fair value of plan assets	193,000	394,000
Defined Benefit Pension Plans \| International \| Level 2
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Defined Benefit Pension Plans \| International \| Level 3
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 0	$ 0
Defined Benefit Pension Plans \| Debt securities:
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	36.00%	33.00%	31.00%
Defined Benefit Pension Plans \| Corporate bonds
Pension plan assets within the fair value hierachy
Fair value of plan assets	$ 5,858,000	$ 6,371,000
Defined Benefit Pension Plans \| Corporate bonds \| Level 1
Pension plan assets within the fair value hierachy
Fair value of plan assets		0
Defined Benefit Pension Plans \| Corporate bonds \| Level 2
Pension plan assets within the fair value hierachy
Fair value of plan assets	5,858,000	6,371,000
Defined Benefit Pension Plans \| Corporate bonds \| Level 3
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0
Chairman and President Non-Qualified Defined Benefit Plans
Pension plan assets within the fair value hierachy
Fair value of plan assets	0	0	$ 0
Plan assets	$ 0	$ 0
Minimum \| Cash and cash equivalents
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	0.00%
Minimum \| Equity securities
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	55.00%
Minimum \| Debt securities:
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	30.00%
Maximum \| Cash and cash equivalents
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	15.00%
Maximum \| Equity securities
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	70.00%
Maximum \| Debt securities:
Plan’s weighted-average asset allocations by asset category
Actual plan asset allocations (in percentage)	40.00%