Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Impairment of goodwill			$ 0	$ 0	$ 40,693
Goodwill			61,074	61,369	61,623
Impairment of long lived assets			$ 0	$ 0	$ 26,320
Scanners and CAD/CAM Services
Goodwill [Line Items]
Impairment of goodwill		$ 40,700
Asset impairment charges	$ 26,300
Impairment of intangible assets	$ 19,300
Impairment of long lived assets		$ 7,000