Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Beginning balance	$ 686,339	$ 575,892
Goodwill from business combinations	4,298	110,447
Ending balance	690,637	686,339
Wealth Management
Goodwill [Roll Forward]
Beginning balance	20,517	20,517
Goodwill from business combinations	701	0
Ending balance	21,218	20,517
Consumer Lending
Goodwill [Roll Forward]
Beginning balance	199,119	168,922
Goodwill from business combinations	984	30,197
Ending balance	200,103	199,119
Commercial Lending
Goodwill [Roll Forward]
Beginning balance	314,260	252,900
Goodwill from business combinations	1,998	61,360
Ending balance	316,258	314,260
Investment Management
Goodwill [Roll Forward]
Beginning balance	152,443	133,553
Goodwill from business combinations	615	18,890
Ending balance	$ 153,058	$ 152,443