Goodwill and Identifiable Intangible Assets - Goodwill by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 366,156	$ 365,500
Goodwill from purchase of insurance book of business during 2015		656
Balance, end of period	366,156	366,156
Adjustment during 2016	0
General Banking [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	321,132	321,132
Goodwill from purchase of insurance book of business during 2015		0
Balance, end of period	321,132	321,132
Adjustment during 2016	0
Insurance [Member]
Goodwill [Roll Forward]
Goodwill, beginning of period	45,024	44,368
Goodwill from purchase of insurance book of business during 2015		656
Balance, end of period	45,024	$ 45,024
Adjustment during 2016	$ 0