Schedule of Net Periodic Pension (Income) Costs (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure
Service cost	$ 3,427	$ 2,787	$ 2,735
Interest cost	13,266	15,670	17,466
Expected return on plan assets	(14,591)	(15,946)	(15,602)
Amortization of prior service cost	164	232	621
Net actuarial (gain) loss	(8,315)	23,237	12,583
Settlement loss			1,567
Total net periodic pension (income) cost	(6,049)	25,980	19,370
Prior service cost	(164)	(232)	(621)
Total recognized in other comprehensive income	(164)	(232)	(621)
Total recognized in net periodic pension (income) cost and other comprehensive income	(6,213)	25,748	18,749
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure
Service cost	75	67	59
Interest cost	342	437	539
Amortization of prior service cost	(598)	(599)	(598)
Net actuarial (gain) loss	(2,025)	83	981
Total net periodic pension (income) cost	(2,206)	(12)	981
Prior service cost	598	599	598
Total recognized in other comprehensive income	598	599	598
Total recognized in net periodic pension (income) cost and other comprehensive income	$ (1,608)	$ 587	$ 1,579