Condensed Parent Company Financial Statements (Statements of Financial Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 322,415	$ 286,167
Loans, net of unearned income	32,079,073	26,800,290
Allowance for loan losses	(379,910)	(158,461)	$ (154,164)
Net loans	31,759,699	26,643,462
Goodwill	645,707	645,220
Total assets	45,080,768	36,620,583	31,244,849
Liabilities and Shareholders’ Equity
Subordinated notes	436,506	436,095
Other borrowings	518,928	418,174
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	253,566	253,566
Shareholders’ equity	4,115,995	3,691,250	$ 3,267,570	$ 2,976,939
Total liabilities and shareholders’ equity	45,080,768	36,620,583
Reportable Legal Entities | Parent Company
Assets
Cash and due from banks	322,607	96,245
Available-for-sale debt securities and equity securities with readily determinable fair value	15,250	14,695
Investment in and receivable from subsidiaries	4,464,747	4,266,278
Loans, net of unearned income	0	75
Allowance for loan losses	0	(5)
Net loans	0	70
Goodwill	8,371	8,371
Other assets	366,209	353,064
Total assets	5,177,184	4,738,723
Liabilities and Shareholders’ Equity
Other liabilities	204,299	188,275
Subordinated notes	436,506	436,095
Other borrowings	166,818	169,537
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	253,566	253,566
Shareholders’ equity	4,115,995	3,691,250
Total liabilities and shareholders’ equity	$ 5,177,184	$ 4,738,723