Per Share Data (Computations of Basic Earnings Per Share and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Basic Earnings per Share:
NET INCOME	$ 12,639	$ 9,660	$ 35,549	$ 29,055
Weighted Average Shares Outstanding (in shares)	22,968,047	22,929,864	22,958,977	22,922,724
Basic Earnings per Share (USD per share)	$ 0.55	$ 0.42	$ 1.55	$ 1.27
Diluted Earnings per Share:
NET INCOME	$ 12,639	$ 9,660	$ 35,549	$ 29,055
Weighted Average Shares Outstanding (in shares)	22,968,047	22,929,864	22,958,977	22,922,724
Potentially Dilutive Shares, Net (in shares)	0	0	0	0
Diluted Weighted Average Shares Outstanding (in shares)	22,968,047	22,929,864	22,958,977	22,922,724
Diluted Earnings per Share (USD per share)	$ 0.55	$ 0.42	$ 1.55	$ 1.27
Anti-dilutive securities excluded from computation of earnings per share (in shares)	0	0	0	0