Stockholders' Equity - Changes in Accumulated Other Comprehensive Income, Net of Tax by Component (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended								3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Unrealized Gains (Losses) on Available-for-Sale Securities [Member]	Sep. 30, 2013 Unrealized Gains (Losses) on Available-for-Sale Securities [Member]	Sep. 30, 2014 Unrealized Gains (Losses) on Available-for-Sale Securities [Member]	Sep. 30, 2013 Unrealized Gains (Losses) on Available-for-Sale Securities [Member]	Sep. 30, 2014 Defined Benefit Plan Adjustments [Member]	Jun. 30, 2014 Defined Benefit Plan Adjustments [Member]	Dec. 31, 2013 Defined Benefit Plan Adjustments [Member]	Sep. 30, 2013 Defined Benefit Plan Adjustments [Member]	Jun. 30, 2013 Defined Benefit Plan Adjustments [Member]	Dec. 31, 2012 Defined Benefit Plan Adjustments [Member]	Sep. 30, 2014 Foreign Currency Adjustments [Member]	Sep. 30, 2013 Foreign Currency Adjustments [Member]	Sep. 30, 2014 Foreign Currency Adjustments [Member]	Sep. 30, 2013 Foreign Currency Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 11,437	$ 6,536	$ 10,753	$ 11,268	$ 11,035	$ 6,766	$ 10,737	$ 10,108	$ (891)	$ (891)	$ (891)	$ (1,952)	$ (1,952)	$ (1,952)	$ 1,293	$ 1,722	$ 907	$ 3,112
Other comprehensive income (loss) before reclassifications	(4,170)	3,414	(866)	1,676	(1,602)	3,522	1,316	3,174							(2,568)	(108)	(2,182)	(1,498)
Amounts reclassified from accumulated other comprehensive income	(1,546)	(960)	(4,166)	(3,954)	(1,546)	(960)	(4,166)	(3,954)
Other Comprehensive Income (Loss), net of tax	(5,716)	2,454	(5,032)	(2,278)	(3,148)	2,562	(2,850)	(780)							(2,568)	(108)	(2,182)	(1,498)
Ending balance	$ 5,721	$ 8,990	$ 5,721	$ 8,990	$ 7,887	$ 9,328	$ 7,887	$ 9,328	$ (891)	$ (891)	$ (891)	$ (1,952)	$ (1,952)	$ (1,952)	$ (1,275)	$ 1,614	$ (1,275)	$ 1,614