Retirement and Security Bonus Plans Retirement and Security Bonus Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Retirement Benefits [Abstract]
401k Employer matching contributions	$ 3.0	$ 3.1
Defined Contribution Retirement Plan Discretionary Employer Contribution	0.3	0.3
Employer contributions, profit sharing retirement plan	0.7	0.7
Retirement and Security Bonus Plans
Cash Surrender Value, Fair Value Disclosure	$ 5.6
Security bonus plan
Retirement and Security Bonus Plans
Initial vesting percentage	25.00%
Minimum vesting period	5 years
Annual vesting percentage after initial period	5.00%
Expense recognized	$ 0.6	$ 0.5

Deferred Compensation Annual Vesting Percentage After Five Years

No definition available.

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- Definition

Deferred Compensation Minimum Vesting Period

+ References

No definition available.

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- Definition

Deferred Compensation Vesting Percentage Initial

+ References

No definition available.

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- Definition

Defined Contribution Retirement Plan Discretionary Employer Contribution

+ References

No definition available.

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- Definition

Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

+ References

No definition available.

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- References

No definition available.

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- Definition

The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 710
-SubTopic 10
-Section 30
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363

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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.

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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