Shareholders Equity - Summary of Activities in Common Stock (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Equity [Abstract]
Stock option exercises, Amount	$ 2,024	$ 1,637
Employee stock plan purchases, Amount	$ 849	$ 670
Stock option exercises, Shares	156	138
Employee stock plan purchases, Shares	10	16