ALLL Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Allowance for loan and lease losses
Balance at beginning of period	$ 129,786	$ 127,608	$ 131,239	$ 129,568
Provision for loan losses	0	4,718	57	5,513
Charge-offs	(2,859)	(2,604)	(6,200)	(7,611)
Recoveries	2,127	1,842	3,958	4,094
Balance at end of period	129,054	131,564	129,054	131,564
Residential Real Estate | Residential Real Estate
Allowance for loan and lease losses
Balance at beginning of period	10,711	10,634	10,631	10,798
Provision for loan losses	(105)	258	173	81
Charge-offs	(49)	(44)	(341)	(47)
Recoveries	138	55	232	71
Balance at end of period	10,695	10,903	10,695	10,903
Commercial | Commercial Real Estate
Allowance for loan and lease losses
Balance at beginning of period	72,328	68,342	72,448	68,515
Provision for loan losses	(196)	2,774	(344)	3,019
Charge-offs	(126)	(190)	(409)	(1,223)
Recoveries	441	319	752	934
Balance at end of period	72,447	71,245	72,447	71,245
Commercial | Other Commercial
Allowance for loan and lease losses
Balance at beginning of period	36,849	38,108	38,160	39,303
Provision for loan losses	(829)	675	(1,744)	672
Charge-offs	(358)	(640)	(1,198)	(2,428)
Recoveries	597	521	1,041	1,117
Balance at end of period	36,259	38,664	36,259	38,664
Consumer and Other | Home Equity
Allowance for loan and lease losses
Balance at beginning of period	5,880	6,040	5,811	6,204
Provision for loan losses	(73)	8	(9)	(194)
Charge-offs	(20)	(7)	(28)	(19)
Recoveries	14	51	27	101
Balance at end of period	5,801	6,092	5,801	6,092
Consumer and Other | Other Consumer
Allowance for loan and lease losses
Balance at beginning of period	4,018	4,484	4,189	4,748
Provision for loan losses	1,203	1,003	1,981	1,935
Charge-offs	(2,306)	(1,723)	(4,224)	(3,894)
Recoveries	937	896	1,906	1,871
Balance at end of period	$ 3,852	$ 4,660	$ 3,852	$ 4,660