Parent Company Information - Schedule of Condensed Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Equity securities	$ 29,378	$ 41,410
Other assets	971,961	717,600
Total Assets	40,686,076	37,436,020
Liabilities and Shareholders’ Equity
Junior subordinated debentures issued to capital trusts	56,065	55,718
Shareholders’ equity	4,592,120	4,384,188	$ 3,350,454	$ 2,533,165
Total Liabilities and Shareholders’ Equity	40,686,076	37,436,020
Parent Company
Assets
Cash	130,163	119,213
Equity securities	2,999	0
Investments in and receivables due from subsidiaries	4,998,795	4,671,578
Other assets	11,133	12,953
Total Assets	5,143,090	4,803,744
Liabilities and Shareholders’ Equity
Dividends payable to shareholders	46,591	45,796
Long-term borrowings	403,413	292,414
Junior subordinated debentures issued to capital trusts	56,065	55,718
Accrued expenses and other liabilities	44,901	25,628
Shareholders’ equity	4,592,120	4,384,188
Total Liabilities and Shareholders’ Equity	$ 5,143,090	$ 4,803,744