Condensed Parent Company Financial Statements (Statements of Financial Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash	$ 392,142	$ 277,534
Loans, net of unearned income	23,820,691	21,640,797
Allowance for loan losses	152,770	137,905	$ 122,291
Net loans	23,667,921	21,502,892
Goodwill	573,141	501,884
Total assets	31,244,849	27,915,970	25,668,553
Liabilities and Shareholders’ Equity
Subordinated notes	139,210	139,088
Other borrowings	393,855	266,123
Junior subordinated debentures	253,566	253,566
Shareholders’ equity	3,267,570	2,976,939	$ 2,695,617	$ 2,352,274
Total liabilities and shareholders’ equity	31,244,849	27,915,970
Reportable Legal Entities | Parent Company
Assets
Cash	37,931	78,045
Available-for-sale debt securities and equity securities with readily determinable fair value	12,765	14,461
Investment in and receivable from subsidiaries	3,660,968	3,249,202
Loans, net of unearned income	1,200	1,845
Allowance for loan losses	0	0
Net loans	1,200	1,845
Goodwill	8,371	8,371
Other assets	206,902	174,781
Total assets	3,928,137	3,526,705
Liabilities and Shareholders’ Equity
Other liabilities	75,609	66,909
Subordinated notes	139,210	139,088
Other borrowings	192,182	90,203
Junior subordinated debentures	253,566	253,566
Shareholders’ equity	3,267,570	2,976,939
Total liabilities and shareholders’ equity	$ 3,928,137	$ 3,526,705