Stock Incentive Plans - Summary of Information Concerning Stock Option Awards (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares, Options outstanding at beginning of period	568,834	533,524
Shares, Assumed from acquisitions		805,507
Shares, Exercised	(88,899)	(140,817)
Shares, Forfeited	(2,182)	(54,962)
Shares, Options outstanding and exercisable at end of period	477,753	1,143,252
Weighted Average Exercise Price, Options outstanding at beginning of period	$ 8.86	$ 11.50
Weighted Average Exercise Price, Assumed from acquisitions		7.39
Weighted Average Price per Share, Exercised	5.61	6.21
Weighted Average Exercise Price, Forfeited	4.34	24.41
Weighted Average Exercise Price, Options outstanding and exercisable at end of period	$ 9.48	$ 8.64