Goodwill and Other Intangible Assets - Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 67,717	$ 57,517
Goodwill, Acquired During Period	44,940	10,200
Goodwill, Ending Balance	112,657	67,717
Banking [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	35,058	35,058
Goodwill, Acquired During Period	43,516	0
Goodwill, Ending Balance	78,574	35,058
Wealth Management [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	15,434	8,625
Goodwill, Acquired During Period	0	6,809
Goodwill, Ending Balance	15,434	15,434
Insurance [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	17,225	13,834
Goodwill, Acquired During Period	1,424	3,391
Goodwill, Ending Balance	$ 18,649	$ 17,225