Benefit Plans - Asset Allocation for the Pension Plan by Asset Category (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0	$ 15,000
Defined Benefit Plan, Information about Plan Assets [Abstract]
Actual Plan Asset Allocations	100.00%	100.00%
Defined Benefit Plan, Expected Return on Plan Assets, Percentage	7.00%
Equity securities
Defined Benefit Plan, Information about Plan Assets [Abstract]
Actual Plan Asset Allocations	82.00%	79.00%
Fixed income and cash equivalents
Defined Benefit Plan, Information about Plan Assets [Abstract]
Actual Plan Asset Allocations	18.00%	21.00%

Defined Benefit Plan, Expected Return on Plan Assets, Percentage

No definition available.

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
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-Publisher FASB
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- Definition

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.

+ References

No definition available.

+ Details

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- References

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-SubTopic 20
-Section 50
-Paragraph 1
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