Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding at beginning of year, Shares	152,896	214,903	262,042
Granted ,Shares	0	0	0
Exercised ,Shares	(51,055)	(50,930)	(8,800)
Forfeited or expired ,Shares	(40,965)	(11,077)	(38,339)
Outstanding at end of year ,Shares	60,876	152,896	214,903
Options exercisable at year-end ,Shares	60,876	152,896	212,643
Weighted Average Exercise Price, Outstanding at beginning of year	$ 26.15	$ 22.40	$ 21.18
Weighted Average Exercise Price, Granted
Weighted Average Exercise Price, Exercised	$ 13.72	$ 10.83	$ 6.21
Weighted Average Exercise Price, Forfeited or expired	$ 31.30	$ 23.77	$ 17.80
Weighted Average Exercise Price, Outstanding at end of year	$ 33.11	$ 26.15	$ 22.40
Weighted Average Exercise Price, Options exercisable at year-end	$ 33.11	$ 26.15	$ 22.57