Changes in accumulated other comprehensive income (loss) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Balance, Foreign Currency Translation Adjustment	$ 3,178
Other comprehensive loss, Foreign Currency Translation Adjustment	(998)
Amounts reclassified from accumulated other comprehensive income, Foreign Currency Translation Adjustment	0	[1]
Balance, Foreign Currency Translation Adjustment	2,180
Balance, Defined Benefit Pension Adjustment	(21,544)
Other comprehensive loss, Defined Benefit Pension Adjustment	0
Amounts reclassified from accumulated other comprehensive income, Defined Benefit Pension Adjustment	331	[1]
Balance, Defined Benefit Pension Adjustment	(21,213)
Balance, Total Accumulated Other Comprehensive (Loss) Income	(18,366)
Other Comprehensive loss	(998)
Amounts reclassified from accumulated other comprehensive income, Total Accumulated Other Comprehensive (Loss) Income	331	[1]
Balance, Total Accumulated Other Comprehensive (Loss) Income	$ (19,033)

[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 June 30, 2013 and $0.3 million net of a $0.2 million tax benefit for the six months ended June 30, 2013. See Note 7, Employer Sponsored Benefit Plans.