Income Taxes - Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Allowance for loan and lease losses	$ 121,614	$ 25,178
Net operating losses and other carryforwards	74,240	70,820
Stock compensation and deferred compensation plans	45,588	42,980
Acquisition-related fair value adjustments	25,721	44,800
Nonaccrual interest	7,823	6,209
Other	8,290	5,516
Deferred tax assets	283,276	195,503
Valuation allowance	(10,828)	(12,840)
Total deferred tax assets, net of valuation allowance	272,448	182,663
Deferred tax liabilities:
Lease financing	296,184	339,691
Investment securities available-for-sale	56,839	16,760
Goodwill and other intangibles	32,494	35,031
Loan fees and discounts	24,572	10,098
Premises and equipment	16,213	30,122
Deferred Income	12,453	0
Prepaid expenses	10,507	9,508
Loan servicing rights	7,666	12,989
Other	4,926	7,862
Total deferred tax liabilities	461,854	462,061
Net deferred tax liabilities	189,406	$ 279,398
State
Deferred tax assets:
Net operating losses and other carryforwards	4,600
Federal
Deferred tax assets:
Net operating losses and other carryforwards	$ 23,100