Reclassifiaction of Pension and Post-retirement Benefit Plan Out of Accumulated Other Comprehensive Loss (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of prior service cost	$ (80)	$ (160)
Recognized net actuarial losses	3,465	6,930
Total reclassifications	3,385	6,770
Tax benefit	1,278	2,556
Total reclassifications, net of tax	$ 2,107	$ 4,214