ALLL Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for loan and lease losses
Balance at beginning of period	$ 129,877	$ 132,386	$ 129,572	$ 129,697
Provision for loan losses	3,327	626	7,938	1,194
Charge-offs	(5,983)	(2,800)	(14,801)	(5,332)
Recoveries	2,355	2,322	6,867	6,975
Balance at end of period	129,576	132,534	129,576	132,534
Residential Real Estate | Residential Real Estate
Allowance for loan and lease losses
Balance at beginning of period	11,522	13,666	12,436	14,427
Provision for loan losses	(10)	108	(946)	(342)
Charge-offs	(44)	(11)	(87)	(366)
Recoveries	12	148	77	192
Balance at end of period	11,480	13,911	11,480	13,911
Commercial | Commercial Real Estate
Allowance for loan and lease losses
Balance at beginning of period	68,503	66,809	65,773	67,877
Provision for loan losses	2,214	0	6,403	(3,490)
Charge-offs	(3,227)	(55)	(5,261)	(342)
Recoveries	735	490	1,310	3,199
Balance at end of period	68,225	67,244	68,225	67,244
Commercial | Other Commercial
Allowance for loan and lease losses
Balance at beginning of period	36,984	37,031	37,823	32,525
Provision for loan losses	696	(1,033)	551	3,407
Charge-offs	(374)	(342)	(1,855)	(1,068)
Recoveries	514	923	1,301	1,715
Balance at end of period	37,820	36,579	37,820	36,579
Consumer and Other | Home Equity
Allowance for loan and lease losses
Balance at beginning of period	7,662	8,629	7,572	8,998
Provision for loan losses	(682)	561	(324)	215
Charge-offs	(15)	(693)	(458)	(891)
Recoveries	16	77	191	252
Balance at end of period	6,981	8,574	6,981	8,574
Consumer and Other | Other Consumer
Allowance for loan and lease losses
Balance at beginning of period	5,206	6,251	5,968	5,870
Provision for loan losses	1,109	990	2,254	1,404
Charge-offs	(2,323)	(1,699)	(7,140)	(2,665)
Recoveries	1,078	684	3,988	1,617
Balance at end of period	$ 5,070	$ 6,226	$ 5,070	$ 6,226