Per Share Data (Computations of Basic Earnings Per Share and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic Earnings per Share:
NET INCOME	$ 11,097	$ 9,839	$ 22,910	$ 19,395
Weighted Average Shares Outstanding (in shares)	22,968,178	22,929,426	22,954,367	22,919,094
Basic Earnings per Share (USD per share)	$ 0.48	$ 0.43	$ 1.00	$ 0.85
Diluted Earnings per Share:
NET INCOME	$ 11,097	$ 9,839	$ 22,910	$ 19,395
Weighted Average Shares Outstanding (in shares)	22,968,178	22,929,426	22,954,367	22,919,094
Potentially Dilutive Shares, Net (in shares)	0	0	0	0
Diluted Weighted Average Shares Outstanding (in shares)	22,968,178	22,929,426	22,954,367	22,919,094
Diluted Earnings per Share (USD per share)	$ 0.48	$ 0.43	$ 1.00	$ 0.85
Anti-dilutive securities excluded from computation of earnings per share (in shares)	0	0	0	0