Earnings per Share - Reconciliation of Basic to Diluted Weighted Average Common Shares Outstanding (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	33,389	33,789	33,473	33,761
Effect of dilutive common shares outstanding	217	260	306	372
Diluted weighted average common shares outstanding	33,606	34,049	33,779	34,133