Net (loss) Income Per Common Share (Narrative) (Details) - Stock Compensation Plan [Member] - $ / shares	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	741,550	641,500
Weighted average price of anti-dilutive options outstanding	$ 24.27	$ 26.35
Exercise of stock options (shares)	19,650

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Number of share options (or share units) exercised during the current period.

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