Goodwill and Intangible Assets - Goodwill Associated with Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Goodwill	$ 193,125	$ 150,909	$ 150,733
Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Goodwill	184,234	142,065
Analytical Solutions Group [Member]
Segment Reporting Information [Line Items]
Goodwill	8,668	8,668
Europe Region Sales & Service Operations [Member]
Segment Reporting Information [Line Items]
Goodwill
Asia Region Sales & Service Operations [Member]
Segment Reporting Information [Line Items]
Goodwill
Foreign Currency Translation [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 223	$ 176