Goodwill and Identifiable Intangible Assets - Goodwill by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 365,500	$ 372,851
Measurement period adjustment during 2014		(7,351)
Balance, end of period	366,156	365,500	$ 372,851
Goodwill from purchase of insurance book of business during 2015	656
General Banking [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	321,132	328,483
Measurement period adjustment during 2014		(7,351)
Balance, end of period	321,132	321,132	328,483
Goodwill from purchase of insurance book of business during 2015	0
Insurance [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	44,368	44,368
Measurement period adjustment during 2014		0
Balance, end of period	45,024	44,368	44,368
Goodwill from purchase of insurance book of business during 2015	$ 656	$ 656	$ 656