Changes in Accumulated Balances of Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net current period other comprehensive income (loss), before tax	$ 21	$ (152)
Net current period other comprehensive income (loss)	4	39
Beginning balance, Total	(81)	360
Other comprehensive income (loss) before reclassifications, Total	26	79
Amounts reclassified from accumulated other comprehensive income (loss), Total	(1)	(192)
Net current period other comprehensive income (loss), Total	25	(113)
Ending balance, Total	(56)	247
Unrealized gains (losses) on available-for-sale marketable securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(90)	224
Other comprehensive income (loss) before reclassifications, before tax	(7)	(15)
Amounts reclassified from accumulated other comprehensive income (loss), before tax	1	(143)
Net current period other comprehensive income (loss), before tax	(6)	(158)
Ending balance, before tax	(96)	66
Unrealized gains (losses) on cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance, before tax	(16)	216
Other comprehensive income (loss) before reclassifications, before tax	28	106
Amounts reclassified from accumulated other comprehensive income (loss), before tax	(1)	(100)
Net current period other comprehensive income (loss), before tax	27	6
Ending balance, before tax	11	222
Estimated tax (expense) benefit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	25	(80)
Other comprehensive income (loss) before reclassifications	5	(12)
Amounts reclassified from accumulated other comprehensive income (loss)	(1)	51
Net current period other comprehensive income (loss)	4	39
Ending balance	$ 29	$ (41)