Basis of Accounting and Consolidation Basis of Accounting and Consolidation (Stock Plans) (Details) - shares |
3 Months Ended | 12 Months Ended | |
---|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
Dec. 31, 2018 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Maximum number of shares to be issued in stock incentive plan (in shares) | 149,983 | ||
Employee Stock Purchase Plan [Abstract] | |||
Employee Discount for Employee Stock Purchase Plan | 5.00% | ||
Employee Stock Purchase Plan, Number Of Shares Authorized | 600,000 | ||
Stock Issued During Period, Shares, Employee Stock Purchase Plans | 782 | 0 | |
Restricted Stock [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Common stock awarded in SI plan (in shares) | 13,250 | ||
Restricted Stock Units (RSUs) [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Common stock awarded in SI plan (in shares) | 15,540 | 28,700 |