Accumulated Other Comprehensive Income - Changes, net of tax, in Accumulated other comprehensive income are as follows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Unrealized Gain on Securities
Balance at January 1, 2013			$ 927
Other comprehensive income (loss) before reclassifications, net of taxes			6,593
Net current period other comprehensive income	1,245	942	4,759	560
Balance at September 30, 2013	5,686		5,686
Amounts reclassified to realized gain			(1,834)
Cumulative Translation Adjustment
Balance at January 1, 2013			19
Other comprehensive income (loss) before reclassifications, net of taxes			(39)
Amounts reclassified to realized gain			(346)
Net current period other comprehensive income	(349)	(62)	(385)	(70)
Balance at September 30, 2013	(366)		(366)
Total
Balance at January 1, 2013			946
Other comprehensive income (loss) before reclassifications, net of taxes			6,554
Amounts reclassified to realized gain			(2,180)
Net current period other comprehensive income			4,374
Balance at September 30, 2013	$ 5,320		$ 5,320