Earnings per Share (Reconciliation between Basic and Diluted Earnings per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	181,875	72,000
Net income for basic and diluted earnings per share	$ 23,475	$ 28,851	$ 48,198	$ 54,561
Basic weighted average shares outstanding	30,504,000	30,528,000	30,490,000	30,526,000
Dilutive effect of stock options and restricted stock awards	204,000	140,000	206,000	110,000
Diluted weighted average shares outstanding	30,708,000	30,668,000	30,696,000	30,636,000
Basic earnings per common share	$ 0.77	$ 0.95	$ 1.58	$ 1.79
Diluted earnings per common share	$ 0.76	$ 0.94	$ 1.57	$ 1.78