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Basis of Accounting and Consolidation Basis of Accounting and Consolidation (Stock Issuance) (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 3 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 15, 2018 | Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2018 | Aug. 16, 2017
Capital Raise [Abstract] |  |  |  |  |
Common stock, par value (in dollars per share) |  | $ 4 |  | $ 4 |
Proceeds from issuance of common stock |  | $ 216 | $ 150 |  |
Capital Raise [Member] |  |  |  |  |
Capital Raise [Abstract] |  |  |  |  |
shares underwriters agreed to purchase |  | 823,799 |  |  |
Shares Issued, Price Per Share | $ 38.00 |  |  |  |
Underwriters Option to Purchase Shares |  | 123,569 |  |  |
Shares, Issued | 947,368 |  |  |  |
Proceeds from issuance of common stock | $ 34,000 |  |  |  |
At The Market Program [Member] |  |  |  |  |
Balance of Common Stock Available Under ATM |  | $ 16,530 |  |  | $ 20,000

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- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The cash inflow from the additional capital contribution to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
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- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
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