Pension 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
Pension Plan and SERP
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 4,813	$ 4,427
Amortization of prior service credit	(8,513)	(7,597)
Amortization of prior service credit	0	0
Amortization of net actuarial loss	152	1,289
Net periodic (benefit) cost	(3,548)	(1,881)
Employer contributions	195	100
Postretirement Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	163	150
Amortization of prior service credit	(200)	(212)
Amortization of prior service credit	(36)	(38)
Amortization of net actuarial loss	176	150
Net periodic (benefit) cost	103	50
Employer contributions	$ 0	$ 0