Condensed Parent Company Financial Statements (Statements of Financial Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash	$ 267,194	$ 271,454
Available-for-sale securities, at fair value	1,724,667	1,716,388
Loans, net of unearned income	19,703,172	17,118,117
Less: Allowance for loan losses	122,291	105,400	$ 91,705
Goodwill	498,587	471,761
Total assets	25,668,553	22,909,348	19,998,840
Liabilities and Shareholders' Equity
Subordinated notes	138,971	138,861	138,800
Other borrowings	262,486	265,785
Junior subordinated debentures	253,566	268,566
Shareholders' equity	2,695,617	2,352,274	$ 2,069,822	$ 1,900,589
Total liabilities and shareholders’ equity	25,668,553	22,909,348
Reportable Legal Entities | Parent Company
Assets
Cash	49,828	116,889
Available-for-sale securities, at fair value	12,926	12,243
Investment in and receivable from subsidiaries	2,979,283	2,600,716
Loans, net of unearned income	2,313	2,820
Less: Allowance for loan losses	0	0
Net Loans	2,313	2,820
Goodwill	8,371	8,371
Other assets	162,047	148,673
Total assets	3,214,768	2,889,712
Liabilities and Shareholders' Equity
Other liabilities	56,462	44,349
Subordinated notes	138,971	138,861
Other borrowings	70,152	85,662
Junior subordinated debentures	253,566	268,566
Shareholders' equity	2,695,617	2,352,274
Total liabilities and shareholders’ equity	$ 3,214,768	$ 2,889,712