Stock Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Number of Shares
Options outstanding at beginning of period	134,644	182,665	318,265
Exercised		(7,500)	(17,250)
Canceled	(7,500)	(40,521)	(118,350)
Options outstanding at end of period	127,144	134,644	182,665
Weighted Average Exercise Price
Options outstanding at beginning of period	$ 19.82	$ 19.11	$ 19.23
Exercised		$ 13.47	$ 15.03
Canceled	$ 13.39	$ 18.45	$ 20.02
Options outstanding at end of year	$ 20.20	$ 19.82	$ 19.11