Other Income and Other Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
All other income and commissions:
Other service charges	$ 3,758	$ 2,954	$ 11,609	$ 9,047
ATM and interchange fees	3,263	3,137	9,943	8,998
Dividend income	2,757	0	8,130	0
Mortgage banking	2,533	1,354	7,510	3,883
Deferred compensation	1,458	1,128	2,900	4,446
Electronic banking fees	1,309	1,282	3,741	3,911
Letter of credit fees	1,307	1,211	3,851	3,369
Insurance commissions	396	567	1,629	2,042
(Gain)/loss on extinguishment of debt	(1)	(14,329)	(1)	(14,329)
Other	5,875	2,739	16,020	7,684
Total	22,655	43	65,332	29,051
All other expense:
Travel and entertainment	3,988	2,798	12,102	8,308
Other insurance and taxes	2,761	2,396	8,178	7,229
Employee training and dues	1,682	1,198	5,310	4,194
Supplies	1,635	928	5,458	2,884
Non-service components of net periodic pension and post-retirement cost	1,585	454	3,619	1,782
Tax credit investments	1,370	762	3,586	2,646
Customer relations	1,328	1,361	3,749	4,240
OREO	1,256	303	2,174	953
Miscellaneous loan costs	543	757	2,720	2,078
Litigation and regulatory matters	(1,541)	8,162	609	8,403
Other	11,094	8,994	64,527	29,837
Total	$ 25,701	$ 28,113	$ 112,032	$ 72,554