Shareholders Equity - Summary of Activities in Common Stock (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity [Abstract]
Stock option exercises, Shares	1,443	1,218	582
Purchases of common stock, Shares			(3,004)
Employee stock plan purchases, Shares	64	81	100
Shares issued for acquisition, Shares		60
Stock option exercises, Amount	$ 18,289	$ 12,443	$ 3,553
Purchases of common stock, Amount			(71,802)
Employee stock plan purchases, Amount	3,542	2,641	2,045
Shares issued for acquisition, Amount		$ 2,815