Costs and Billings on Uncompleted Contracts - Schedule of Information Regarding Contracts Accounted for Under Percentage-of-Completion Method (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Receivables [Abstract]
Cumulative revenues recognized on uncompleted contracts	$ 113.9	$ 76.9
Cumulative billings on uncompleted contracts	113.3	71.2
Revenues and billing on uncompleted contracts	$ 0.6	$ 5.7

Cumulative difference between revenues and billings on uncompleted contracts accounted for under the percentage of completion method.

No definition available.

Name:	npo_RevenuesBillingsOnUncompletedContracts
Namespace Prefix:	npo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant