Stock-based Compensation (Performance Retention Awards, Present Value Calculation Assumptions) (Details) - Performance Retention Awards [Member]	12 Months Ended
Dec. 31, 2019 $ / shares
Assumptions For Stock Awards [Abstract]
Dividend per share per quarter	$ 0.88
Risk-free interest rate at date of grant	2.50%

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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 (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Period Type:	duration