Per Share Data (Computations of Basic Earnings Per Share and Diluted Earnings Per Share) (Details) $ / shares in Units, $ in Thousands			3 Months Ended				9 Months Ended
		Apr. 21, 2017	Sep. 30, 2017 USD ($) $ / shares shares		Sep. 30, 2016 USD ($) $ / shares shares		Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) $ / shares shares
Basic Earnings per Share:
NET INCOME | $			$ 9,660		$ 10,185		$ 29,055	$ 25,119
Weighted Average Shares Outstanding (in shares)	[1]		22,929,864		22,886,721		22,922,724	22,221,780
Basic Earnings per Share (USD per share) | $ / shares	[2]		$ 0.42	[1]	$ 0.45	[1]	$ 1.27	$ 1.13
Diluted Earnings per Share:
NET INCOME | $			$ 9,660		$ 10,185		$ 29,055	$ 25,119
Weighted Average Shares Outstanding (in shares)	[1]		22,929,864		22,886,721		22,922,724	22,221,780
Potentially Dilutive Shares, Net (in shares)			0	[1]	0	[1]	0	2,639
Diluted Weighted Average Shares Outstanding (in shares)	[1]		22,929,864		22,886,721		22,922,724	22,224,419
Diluted Earnings per Share (USD per share) | $ / shares	[2]		$ 0.42	[1]	$ 0.45	[1]	$ 1.27	$ 1.13
Anti-dilutive securities excluded from computation of earnings per share (in shares)			0		0		0	0
Stock split, conversion ratio		0.6667

[1] Share and per share data has been adjusted to reflect a 3-for-2 stock split on April 21, 2017.

[2] Per share data has been adjusted to reflect a 3-for-2 stock split on April 21, 2017.