Summary of Changes in Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Schedule of Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on available-for-sale marketable securities, Beginning balance	$ 922
Other comprehensive income before reclassifications, Unrealized gains (losses) on available-for-sale marketable securities	363
Amounts reclassified from accumulated other comprehensive income, Unrealized gains (losses) on available-for-sale marketable securities	(163)	(71)
Net change	200	1,096
Unrealized gains (losses) on available-for-sale marketable securities, Ending balance	1,122
Unrealized gains (losses) on Cash Flow Hedges, Beginning balance	483
Other comprehensive income before reclassifications, Unrealized gains (losses) on Cash Flow Hedges	176	523
Amounts reclassified from accumulated other comprehensive income, Unrealized gains (losses) on Cash Flow Hedges	(141)	39
Net current period other comprehensive income, Unrealized gains (losses) on Cash Flow Hedges	35	562
Unrealized gains (losses) on Cash Flow Hedges, Ending balance	518
Unrealized gains (losses) on components of defined benefit plans, Beginning balance	(237)
Other comprehensive income before reclassifications, Unrealized gains (losses) on components of defined benefit plans
Amounts reclassified from accumulated other comprehensive income, Unrealized gains (losses) on components of defined benefit plans	3
Net current period other comprehensive income, Unrealized gains (losses) on components of defined benefit plans	3
Unrealized gains (losses) on components of defined benefit plans, Ending balance	(234)
Unrealized gains (losses) on foreign currency translation, Beginning balance	(180)
Other comprehensive income before reclassifications, Unrealized gains (losses) on foreign currency translation	(36)
Amounts reclassified from accumulated other comprehensive income, Unrealized gains (losses) on foreign currency translation
Net current period other comprehensive income, Unrealized gains (losses) on foreign currency translation	(36)	22
Unrealized gains (losses) on foreign currency translation, Ending balance	(216)
Accumulated other comprehensive Income, Total, Beginning balance	988
Other comprehensive income before reclassifications, Total	503
Amounts reclassified from accumulated other comprehensive income, Total	(301)
Net current period other comprehensive income, Total	202	1,680
Accumulated other comprehensive Income, Total, Ending balance	$ 1,190