Stock and Incentive Compensation Plans - Compensation Expense for Awards Under Stock Plan (Details) - Stock and Incentive Compensation Plan [Member] - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Compensation expense [Abstract]
Recognized compensation expense	$ 4,787	$ 3,870	$ 4,309
Unrecognized compensation expense	5,640
Performance Based Award [Member]
Compensation expense [Abstract]
Recognized compensation expense	1,524	861	1,387
Unrecognized compensation expense	$ 1,914
Weighted average life of unrecognized compensation expense	1 year 7 months 2 days
Time-Vested Awards [Member]
Compensation expense [Abstract]
Recognized compensation expense	$ 3,263	$ 3,009	$ 2,922
Unrecognized compensation expense	$ 3,726
Weighted average life of unrecognized compensation expense	1 year 8 months 23 days

Compensation expense stock and incentive plans.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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