Summary of Treasury Stock Activity (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) shares
Schedule of Treasury Stock [Line Items]
Beginning Balance, Shares | shares	4,183,504
Restricted stock withholdings | shares	206,502	[1]
Restricted stock forfeitures | shares	54,210
Ending Balance, Shares | shares	4,444,216
Beginning Balance, Cost | $	$ 66,577
Restricted stock withholdings | $	6,828	[1]
Restricted stock forfeitures | $	0
Ending Balance, Cost | $	$ 73,405

[1] The Company withheld restricted shares as a result of the election by certain employees to satisfy their tax liabilities upon vesting in restricted stock and restricted stock units. The Company determined the number of shares to be withheld based upon market values ranging from $29.17 to $38.11 per share.