Summary of Treasury Stock Activity (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) shares
Schedule of Treasury Stock [Line Items]
Beginning Balance, Shares | shares	4,183,504
Restricted stock withholdings | shares	167,252	[1]
Restricted stock forfeitures | shares	30,170
Ending Balance, Shares | shares	4,380,926
Beginning Balance, Cost | $	$ 66,577
Restricted stock withholdings | $	5,610	[1]
Restricted stock forfeitures | $	0
Ending Balance, Cost | $	$ 72,187

[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 $32.49 to $35.80 per share.