Stock-Based Compensation - Information about Deferred Tax Benefits Recognized Related to Restricted Stock Awards, Paid Dividends and the Fair Value of Vested Restricted Stock (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefits realized			$ 603	$ 0
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred tax benefits recognized	875	748	2,544	1,313
Tax benefits realized	80	612	781	892
Fair value of vested restricted stock	$ 75	$ 648	$ 960	$ 1,027