ACL Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Allowance for credit losses
Balance at beginning of period	$ 124,490	$ 131,239
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	3,720
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	49
Financing Receivable, Credit Loss, Expense (Reversal)	22,744	57
Charge-offs	(2,567)	(3,341)
Recoveries	1,754	1,831
Balance at end of period	150,190	129,786
Residential Real Estate
Allowance for credit losses
Balance at beginning of period	10,111	10,631
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	3,584
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0
Financing Receivable, Credit Loss, Expense (Reversal)	(4,369)	278
Charge-offs	(20)	(292)
Recoveries	9	94
Balance at end of period	9,315	10,711
Commercial Real Estate
Allowance for credit losses
Balance at beginning of period	69,496	72,448
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	10,533
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	49
Financing Receivable, Credit Loss, Expense (Reversal)	(9,433)	(148)
Charge-offs	(30)	(283)
Recoveries	470	311
Balance at end of period	71,085	72,328
Other Commercial
Allowance for credit losses
Balance at beginning of period	36,129	38,160
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	(13,759)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0
Financing Receivable, Credit Loss, Expense (Reversal)	34,133	(915)
Charge-offs	(785)	(840)
Recoveries	454	444
Balance at end of period	56,172	36,849
Home Equity
Allowance for credit losses
Balance at beginning of period	4,937	5,811
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	3,400
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0
Financing Receivable, Credit Loss, Expense (Reversal)	(508)	64
Charge-offs	(1)	(8)
Recoveries	106	13
Balance at end of period	7,934	5,880
Other Consumer
Allowance for credit losses
Balance at beginning of period	3,817	4,189
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	(38)
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0
Financing Receivable, Credit Loss, Expense (Reversal)	2,921	778
Charge-offs	(1,731)	(1,918)
Recoveries	715	969
Balance at end of period	$ 5,684	$ 4,018