Shareholders' Equity and Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jan. 23, 2017
Earnings Per Share Reconciliation [Abstract]
Net income		$ 5,931	$ 6,438	$ 11,905	$ 10,538
Weighted average shares outstanding (in shares)	[1]	21,331	21,281	21,320	21,516
Effect of stock options (in shares)		143	148	147	150
Stock units for deferred compensation plan for non-employee directors (in shares)		119	114	119	114
Performance share units (in shares)		54	41	57	37
Restricted stock units (in shares)		0	55	0	70
Weighted average shares outstanding for calculation of diluted earnings per share (in shares)		21,647	21,639	21,643	21,887
Net income per common share [Abstract]
Basic (in dollars per share)	[1]	$ 0.28	$ 0.30	$ 0.56	$ 0.49
Diluted (in dollars per share)		$ 0.27	$ 0.30	$ 0.55	$ 0.48
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	30	0	30

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