Net income per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Reconciliation [Abstract]
Net income from continuing operations	$ 68	$ 1,264
Basic:
Shares outstanding at beginning of period (in shares)			15,949,000	15,771,000
Weighted average shares (repurchased) during the period, net (in shares)	1,000
Weighted average shares issued during the period, net (in shares)		10,000
Weighted average common shares, basic (in shares)	15,948,000	15,781,000
Net income from continuing operations per common share, basic (in dollars per shares)	$ 0.00	$ 0.08
Diluted:
Weighted average common shares, basic (in shares)	15,948,000	15,781,000
Dilutive impact of stock options and restricted stock awards (in shares)	338,000	197,000
Weighted average common shares, diluted (in shares)	16,286,000	15,978,000
Net income from continuing operations per common share, diluted (in dollars per share)	$ 0.00	$ 0.08
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive stock options outstanding (in shares)	0	0