Loss Per Common Share (Computation Of Basic And Diluted (Loss) Income Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic income (loss) per common share
Net income (loss)	$ 10,582	$ (2,870)	$ 5,266	$ (13,224)
Net loss allocated to participating securities	(63)	20	(34)	93
Net loss allocated to common shareholders	$ 10,519	$ (2,850)	$ 5,232	$ (13,131)
Basic weighted-average common shares outstanding	39,086	37,912	38,924	37,608
Basic loss per common share	$ 0.27	$ (0.08)	$ 0.13	$ (0.35)
Diluted income (loss) per common share
Net income (loss)	$ 10,582	$ (2,870)	$ 5,266	$ (13,224)
Net (income) loss allocated to participating securities	(55)	20	(34)	93
Net loss attributable to convertible senior notes	919
Net income (loss) allocated to common shareholders	$ 11,446	$ (2,850)	$ 5,232	$ (13,131)
Basic weighted-average common shares outstanding	39,086	37,912	38,924	37,608
Effect of dilutive stock options and awards	505		572
Effect of convertible senior notes	4,862
Diluted weighted-average common shares outstanding	44,453	37,912	39,496	37,608
Diluted loss per common share	$ 0.26	$ (0.08)	$ 0.13	$ (0.35)