Accrued Liabilities - Components of Accrued liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Other Liabilities Disclosure [Abstract]
Personnel expense	$ 15,727	$ 20,872
Workers' compensation	15,281	15,754
Deferred revenue	11,952
Professional fees	870	2,145
Insurance	2,150	2,253
Utilities	1,607	1,844
Taxes	1,097	1,745
Tooling	712	686
Other	3,289	3,125
Total accrued liabilities	$ 52,685	$ 48,424