Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss on cash flow hedges Interest rate swaps	$ 215
Total reclassifications for the period	578	[1],[2]
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss on cash flow hedges Interest rate swaps	301
Gains and losses on cash flow hedges Interest rate swaps, reclassifications for the period, Total before tax	301
Gains and losses on cash flow hedges Interest rate swaps, reclassifications for the period, Provision for income taxes	(114)
Gains and losses on cash flow hedges Interest rate swaps, reclassifications for the period, Net of tax	187	[1],[2]
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of defined benefit pension and other post retirement benefit items, prior-service costs	(346)	[3]
Amortization of defined benefit pension and other post retirement benefit items, actuarial gains/(losses)	752	[3]
Amortization of defined benefit pension and other post retirement benefit items, reclassifications for the period, Total before tax	406
Amortization of defined benefit pension and other post retirement benefit items, reclassifications for the period, Tax (expense) or benefit	(15)
Amortization of defined benefit pension and other post retirement benefit items, reclassifications for the period, Net of tax	$ 391	[1],[2]

[1] All amounts are net of tax. Amounts in parentheses indicate debits.

[2] See the following table for details concerning these reclassifications.

[3] (3) These components are included in the computation of net periodic benefit cost (see Note 7 "Pension and Other Postretirement Benefits" for additional details).