Reconciliation of Weighted Average Shares for Basic and Diluted Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation Of Basic Weighted Average Shares To Diluted Weighted Average Shares [Line Items]
Weighted average shares for basic earnings per share	17,246,717	24,253,657	25,131,811
Weighted average shares for diluted earnings per share	17,547,061	24,505,851	25,331,420
Restricted Stock
Reconciliation Of Basic Weighted Average Shares To Diluted Weighted Average Shares [Line Items]
Non-vested restricted stock and options	187,526	148,669	100,546
Stock Options
Reconciliation Of Basic Weighted Average Shares To Diluted Weighted Average Shares [Line Items]
Non-vested restricted stock and options	112,818	103,525	99,063