Shareholders' Equity and Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Jan. 22, 2018
Earnings Per Share Reconciliation [Abstract]
Net Income		$ 9,161	$ 5,974
Weighted average shares outstanding (in shares)	[1]	21,365	21,308
Effect of stock options (in shares)		135	152
Stock units for deferred compensation plan for non-employee directors (in shares)		125	119
Performance share units (in shares)		49	60
Weighted average shares outstanding for calculation of diluted earnings per share (in shares)		21,674	21,639
Net income per common share [Abstract]
Basic (in dollars per share)	[1]	$ 0.43	$ 0.28
Diluted (in dollars per share)		$ 0.42	$ 0.28
Common Stock [Member]
Class of Stock [Line Items]
Stock repurchase program percentage of shares authorized to be repurchased				5.00%
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of diluted loss per share (in shares)		0	0

[1] Basic net income per common share includes weighted average common shares outstanding during the period and participating share awards.