Fair Value - Financial Instruments not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Lease and lease commitments excluded
Financing leases	$ 246,000	$ 202,500
Deposit liabilities with no defined or contractual maturity	16,300,000	13,900,000
Capital lease obligations	10	19
Book Value
Financial assets:
Cash and cash equivalents	816,329	694,017
Loans held for sale	34,669	904
Loans	13,253,992	13,009,167
Financial liabilities:
Time Deposits	2,614,820	2,510,157
Short-term borrowings		400,000
Long-term borrowings	200,000	200,000
Estimated Fair Value
Financial assets:
Cash and cash equivalents	816,329	694,017
Loans held for sale	42,470	904
Loans	13,514,767	13,140,898
Financial liabilities:
Time Deposits	2,626,481	2,501,478
Short-term borrowings		401,709
Long-term borrowings	215,254	207,104
Estimated Fair Value | Level 1
Financial assets:
Cash and cash equivalents	333,744	360,375
Estimated Fair Value | Level 2
Financial assets:
Cash and cash equivalents	482,585	333,642
Loans held for sale	42,470	904
Financial liabilities:
Time Deposits	2,626,481	2,501,478
Short-term borrowings		401,709
Long-term borrowings	215,254	207,104
Estimated Fair Value | Level 3
Financial assets:
Loans	$ 13,514,767	$ 13,140,898