Certain Information Regarding Health and Welfare Plan (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in Plan Assets:
Fair value of assets at end of year	$ 219,330
Post-Retirement Benefits
Change in Benefit Obligation:
Benefit obligation at beginning of year	20,319	17,155
Service cost	4	7	5
Interest cost	683	641	720
Actuarial (gain) loss	(1,972)	3,293
Premiums and claims paid	(712)	(777)
Benefit obligation at end of year	18,322	20,319	17,155
Change in Plan Assets:
Fair value of assets at beginning of year
Employer contribution	712	777
Premiums and claims paid	(712)	(777)
Fair value of assets at end of year
Funded status (included in "Other liabilities")	(18,322)	(20,319)
Changes recognized in other comprehensive income for the year ended December 31:
Amortization of prior service cost	249	249
Amortization of actuarial gain	(657)	(505)
Net actuarial (gain) loss arising during the year	(1,972)	3,293
Total recognized in other comprehensive loss for the year (pre-tax)	(2,380)	3,037
Accumulated other comprehensive loss (pre-tax) not yet recognized in net periodic benefit cost at December 31:
Prior service cost	(2,031)	(2,280)
Actuarial loss, net	7,636	10,265
Total accumulated other comprehensive loss (pre-tax)	$ 5,605	$ 7,985