Changes in accumulated other comprehensive income (loss) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Balance, Foreign Currency Translation Adjustment	$ 3,178
Other comprehensive income, Foreign Currency Translation Adjustment	1,774
Amounts reclassified from accumulated other comprehensive income, Foreign Currency Translation Adjustment	0	[1]
Balance, Foreign Currency Translation Adjustment	4,952
Balance, Defined Benefit Pension Adjustment	(21,544)
Other comprehensive income, Defined Benefit Pension Adjustment	0
Amounts reclassified from accumulated other comprehensive income, Defined Benefit Pension Adjustment	497	[1]
Balance, Defined Benefit Pension Adjustment	(21,047)
Balance, Total Accumulated Other Comprehensive (Loss) Income	(18,366)
Other Comprehensive income, Total Accumulated Other Comprehensive (Loss) Income	1,774
Amounts reclassified from accumulated other comprehensive income, Total Accumulated Other Comprehensive (Loss) Income	497	[1]
Balance, Total Accumulated Other Comprehensive (Loss) Income	$ (16,095)

[1] Amount represents amortization of actuarial losses, a component of net periodic benefit cost. This amount was $0.2 million, net of a $0.1 million tax benefit, for the quarter ended September 30, 2013, and $0.5 million, net of a $0.3 million tax benefit, for the nine months ended September 30, 2013. See Note 7, Employer Sponsored Benefit Plans.