Stock Incentive Plans - Summary of Information Concerning Stock Option Awards (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2015	Jun. 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		304,785
Shares, Exercised	(82,810)	(134,687)
Shares, Forfeited	(2,182)	(52,262)
Shares, Options outstanding and exercisable at end of period	483,842	651,360
Weighted Average Exercise Price, Options outstanding at beginning of period	$ 8.86	$ 11.50
Weighted Average Exercise Price, Assumed from acquisitions		5.77
Weighted Average Price per Share, Exercised	5.57	6.24
Weighted Average Exercise Price, Forfeited	4.34	25.03
Weighted Average Exercise Price, Options outstanding and exercisable at end of period	$ 9.44	$ 8.82