Acquisitions - Unaudited Pro Forma Operating Results (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
(Unaudited Pro Forma) Earnings per share:
Basic (shares)	17,216	17,055	17,189	17,028
Diluted (shares)	17,349	17,267	17,339	17,270
Interface
(Unaudited Pro Forma)
Net sales	$ 220,937	$ 214,503	$ 678,418	$ 627,197
Net income	$ 6,147	$ 8,474	$ 28,461	$ 26,061
(Unaudited Pro Forma) Earnings per share:
Basic (USD per share)	$ 0.36	$ 0.50	$ 1.66	$ 1.53
Diluted (USD per share)	$ 0.35	$ 0.49	$ 1.64	$ 1.51

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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