Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenues	$ 157,941	$ 152,976	$ 304,574	$ 293,258
Operating profit (loss)	593	2,164	256	(274)
Net income (loss)	(874)	1,239	(1,292)	(119)
Operating segments | HBB
Segment Reporting Information [Line Items]
Revenues	135,869	127,574	261,283	241,728
Operating profit (loss)	4,399	5,164	8,392	5,946
Net income (loss)	1,967	3,195	4,769	3,884
Operating segments | KC
Segment Reporting Information [Line Items]
Revenues	22,762	25,868	44,862	52,533
Operating profit (loss)	(3,834)	(3,008)	(8,138)	(6,287)
Net income (loss)	(2,900)	(1,970)	(6,538)	(4,113)
Eliminations
Segment Reporting Information [Line Items]
Revenues	(690)	(466)	(1,571)	(1,003)
Operating profit (loss)	28	8	2	67
Net income (loss)	$ 59	$ 14	$ 477	$ 110