Income Taxes Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Allowance for credit losses	$ 67,059	$ 37,081
Tax credit carryforwards	39,294	43,133
State loss carryforwards	20,401	16,324
Tax credit investments	10,159	6,799
Other accrued expenses	9,801	8,797
Deferred compensation	8,486	7,752
Stock-based compensation	3,289	2,930
Postretirement and defined benefit plans	1,553	599
Other	12,107	4,246
Total gross deferred tax assets	172,149	127,661
Deferred tax liabilities:
Equipment lease financing	44,216	42,273
Unrealized holding gains on AFS securities	23,978	4,223
Premises and equipment	8,876	6,282
MSRs	6,414	8,686
Acquisition premiums/discounts	5,466	5,266
Intangible assets	1,205	1,136
Other	15,811	12,387
Total gross deferred tax liabilities	105,966	80,253
Net deferred tax asset, before valuation allowance	66,183	47,408
Valuation allowance	(20,401)	(16,324)
Net deferred tax asset	45,782	31,084
State and local operating loss carryforwards	263,600	$ 392,000
Tax credit carryforwards related to TCIs	$ 39,300