Employee Benefit Plans (Balance Sheet Impact, Including Benefit Obligations, Assets and Funded Status) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in projected benefit obligation:
Service costs	$ 1,915	$ 1,712	$ 2,167
Interest costs	26,861	29,068	30,152
Change in plan assets:
Plan assets at fair value at beginning of year	294,216
Plan assets at fair value at end of year	313,469	294,216
Defined Benefit Pension Plans
Change in projected benefit obligation:
Benefit obligation at beginning of year	424,462	385,756
Service costs
Interest costs	17,340	18,445
Plan amendment
Actuarial (gains) losses	(38,766)	37,030
Benefits paid	(21,001)	(16,769)
Projected benefit obligation at end of year	382,035	424,462
Change in plan assets:
Plan assets at fair value at beginning of year	294,216	257,078
Actual return on plan assets	10,971	33,236
Contributions	29,283	20,671
Benefits paid	(21,001)	(16,769)
Plan assets at fair value at end of year	313,469	294,216
Reconciliation of funded status, Unfunded status of the plans	(68,566)	(130,246)
Amounts recognized in the consolidated balance sheet, Accrued benefit liability	(68,566)	(130,246)
Unrecognized net actuarial loss	162,084	215,405
Unrecognized prior service cost (credit)	40	65
Amounts recognized in accumulated other comprehensive income	162,124	215,470
Accumulated benefit obligation at end of year	382,035	424,462
Unfunded Supplemental Benefit Plans
Change in projected benefit obligation:
Benefit obligation at beginning of year	250,226	223,516
Service costs	1,915	1,712
Interest costs	9,521	10,623
Plan amendment	2,088
Actuarial (gains) losses	(24,233)	27,226
Benefits paid	(13,059)	(12,851)
Projected benefit obligation at end of year	226,458	250,226
Change in plan assets:
Plan assets at fair value at beginning of year
Actual return on plan assets
Contributions	13,059	12,851
Benefits paid	(13,059)	(12,851)
Plan assets at fair value at end of year
Reconciliation of funded status, Unfunded status of the plans	(226,458)	(250,226)
Amounts recognized in the consolidated balance sheet, Accrued benefit liability	(226,458)	(250,226)
Unrecognized net actuarial loss	90,303	124,183
Unrecognized prior service cost (credit)	(29,142)	(35,639)
Amounts recognized in accumulated other comprehensive income	61,161	88,544
Accumulated benefit obligation at end of year	$ 226,458	$ 250,226