Earnings Per Share (Reconciliation of Weighted Average Shares Used to Determine Basic and Diluted Earnings Per Share) (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Basic average common shares outstanding (in shares)	16,871	16,746	16,662
Effect of dilutive options and restricted stock awards (in shares)	370	338	341
Diluted average common shares outstanding (in shares)	17,241	17,084	17,003