Quarterly Financial Information (Unaudited) Quarterly Financial Information (Unaudited) - Components of Gross Profit and Net Income (Details) - USD ($)	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Gross profit impact of inventory step-up purchase accounting adjustments	$ 0	$ 83,000	$ 543,000	$ 481,000	$ 347,000	$ 1,607,000	$ 0	$ 0
Gross profit impact of restructuring, severance, and segment consolidation expenses	155,000	287,000	92,000	441,000	0	0	0	0
Net income impact of inventory step-up purchase accounting adjustments	0	59	394	350	254	1,176	0	0
Net income impact of restructuring, severance, and segment consolidation expenses	488	910	216	702	0	0	0	0
Net income impact of long-lived asset impairment charges	0	0	0	490	0	0	0	0
Net income impact of strategic initiatives expenses	205	219	0	125	786	820	1,080	365
Net income impact of German Cartel settlement	$ 0	$ 0	$ 0	$ 0	$ 3,479	$ 0	$ 0	$ 0