Employee Retirement and Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 770	$ 923
Interest cost	3,495	3,128
Expected return on plan assets	(4,690)	(4,633)
Unrecognized transition obligation	0	0
Prior service cost	197	198
Unrecognized net loss	1,276	3,098
Net periodic benefit cost	1,048	2,714
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	206	204
Interest cost	416	306
Prior service cost	16	6
Unrecognized net loss	19	75
Net periodic benefit cost	$ 657	$ 591