Retirement Plans - Funded Status and Accrued Pension Cost (Detail) (Pension Plans, Defined Benefit [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans, Defined Benefit [Member]
CHANGE IN BENEFIT OBLIGATION:
Benefit obligation at beginning of year	$ 96,384	$ 92,575
Interest cost	3,376	3,655	4,151
Actuarial (gain) loss	(11,560)	5,998
Benefits paid	(7,299)	(5,844)
Benefit obligation at end of year	80,901	96,384	92,575
CHANGE IN PLAN ASSETS:
Fair value of plan assets at beginning of year	69,611	62,265
Actual return on plan assets	11,044	9,061
Employer contributions	1,620	4,129
Benefits paid	(7,299)	(5,844)
Fair value of plan assets at end of year	74,976	69,611	62,265
Funded status and accrued pension cost	$ (5,925)	$ (26,773)