Earnings Per Common Share (Reconciliation of Numerators and Denominators ) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic EPS:
Net income	$ 23,297	$ 25,019	$ 57,829	$ 71,163
Less: income allocated to participating securities	(67)	(119)	(279)	(329)
Basic EPS per common share	$ 23,230	$ 24,900	$ 57,550	$ 70,834
Basic (in shares)	28,857,111	29,542,001	28,962,576	29,585,383
Basic (in dollars per share)	$ 0.81	$ 0.84	$ 1.99	$ 2.39
Diluted EPS:
Net income	$ 23,297	$ 25,019	$ 57,829	$ 71,163
Effect of Dilutive Securities	0	0	0	0
Diluted EPS per common share	$ 23,297	$ 25,019	$ 57,829	$ 71,163
Basic (in shares)	28,857,111	29,542,001	28,962,576	29,585,383
Effect of Dilutive Securities (in shares)	82,907	142,104	140,377	174,076
Diluted (in shares)	28,940,018	29,684,105	29,102,953	29,759,459
Diluted (in dollars per share)	$ 0.81	$ 0.84	$ 1.99	$ 2.39