Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Goodwill And Other Intangible Assets [Line Items]
Beginning Balance	$ 228,346	$ 209,758
Acquisition of Marquette	50	18,588
Ending Balance	228,396	228,346
Bank [Member]
Goodwill And Other Intangible Assets [Line Items]
Beginning Balance	161,341	142,753
Acquisition of Marquette	50	18,588
Ending Balance	161,391	161,341
Institutional Investment Management [Member]
Goodwill And Other Intangible Assets [Line Items]
Beginning Balance	47,529	47,529
Ending Balance	47,529	47,529
Asset Servicing [Member]
Goodwill And Other Intangible Assets [Line Items]
Beginning Balance	19,476	19,476
Ending Balance	$ 19,476	$ 19,476