Accumulated Other Comprehensive Income - Changes, net of tax, in Accumulated other comprehensive income are as follows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ 946
Unrealized gain (loss) - pretax	12,063
Tax effect on unrealized gain (loss)	(4,490)
Unrealized gain - net of tax	7,573
Reclassification to realized gain - pretax	(2,969)
Tax effect on reclassification	966
Reclassification to realized gain - net of tax	2,003
Net current period other comprehensive income (loss)	5,570	203	(2,118)
Balance, end of period	6,516	946
Unrealized Gain on Securities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	927
Unrealized gain (loss) - pretax	12,126
Tax effect on unrealized gain (loss)	(4,490)
Unrealized gain - net of tax	7,636
Reclassification to realized gain - pretax	(2,608)
Tax effect on reclassification	966
Reclassification to realized gain - net of tax	1,642
Net current period other comprehensive income (loss)	5,994
Balance, end of period	6,921
Cumulative Translation Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	19
Unrealized gain (loss) - pretax	(63)
Tax effect on unrealized gain (loss)	0
Unrealized gain - net of tax	(63)
Reclassification to realized gain - pretax	(361)
Tax effect on reclassification	0
Reclassification to realized gain - net of tax	361
Net current period other comprehensive income (loss)	(424)
Balance, end of period	$ (405)