ALLL Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Allowance for loan and lease losses
Balance at beginning of period	$ 132,386	$ 130,519	$ 129,697	$ 129,753
Provision for loan losses	626	826	1,194	1,873
Charge-offs	(2,800)	(2,073)	(5,332)	(4,671)
Recoveries	2,322	1,496	6,975	3,813
Balance at end of period	132,534	130,768	132,534	130,768
Residential Real Estate | Residential Real Estate
Allowance for loan and lease losses
Balance at beginning of period	13,666	14,850	14,427	14,680
Provision for loan losses	108	854	(342)	1,036
Charge-offs	(11)	(20)	(366)	(78)
Recoveries	148	24	192	70
Balance at end of period	13,911	15,708	13,911	15,708
Commercial | Commercial Real Estate
Allowance for loan and lease losses
Balance at beginning of period	66,809	68,697	67,877	67,799
Provision for loan losses	0	(657)	(3,490)	(452)
Charge-offs	(55)	(921)	(342)	(1,669)
Recoveries	490	907	3,199	2,348
Balance at end of period	67,244	68,026	67,244	68,026
Commercial | Other Commercial
Allowance for loan and lease losses
Balance at beginning of period	37,031	31,483	32,525	30,891
Provision for loan losses	(1,118)	195	3,256	1,839
Charge-offs	(131)	(367)	(722)	(1,736)
Recoveries	797	290	1,520	607
Balance at end of period	36,579	31,601	36,579	31,601
Consumer and Other | Home Equity
Allowance for loan and lease losses
Balance at beginning of period	8,629	8,946	8,998	9,963
Provision for loan losses	561	397	215	(621)
Charge-offs	(693)	(433)	(891)	(586)
Recoveries	77	136	252	290
Balance at end of period	8,574	9,046	8,574	9,046
Consumer and Other | Other Consumer
Allowance for loan and lease losses
Balance at beginning of period	6,251	6,543	5,870	6,420
Provision for loan losses	1,075	37	1,555	71
Charge-offs	(1,910)	(332)	(3,011)	(602)
Recoveries	810	139	1,812	498
Balance at end of period	$ 6,226	$ 6,387	$ 6,226	$ 6,387