Segment Reporting - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jul. 01, 2012
Disclosure Segment Reporting Additional Information [Abstract]
Number of reportable segments	3
Assets	$ 570,167,000	$ 556,270,000	$ 869,290,000		$ 560,802,000
Total sales to major customer		$ 164,900,000	$ 187,400,000	$ 156,800,000