Fair Value Measurement (Schedule Of Carrying Value And Fair Value Of Financial Instruments Not Recorded At Fair Value) (Details) - USD ($)	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
FINANCIAL ASSETS:
Equity and other investment securities	$ 64,764,000		$ 61,841,000
Investment securities available for sale	2,842,076,000		2,977,108,000
Investment securities held to maturity	3,320,000		3,606,000
Loans held for sale, at fair value	355,022,000		166,461,000
Loans and leases, net	21,364,506,000		20,277,795,000
Restricted equity securities	54,463,000		40,268,000
Residential mortgage servicing rights	151,383,000	$ 139,780,000	169,025,000	$ 175,038,000	$ 166,217,000	$ 153,151,000
Bank owned life insurance	318,533,000		313,626,000
Derivatives	200,412,000		49,484,000
FINANCIAL LIABILITIES:
Deposits	22,434,734,000		21,137,486,000
Securities sold under agreements to repurchase	296,717,000		297,151,000
Borrowings	1,106,674,000		751,788,000
Junior subordinated debentures, at fair value	267,798,000		300,870,000
Junior subordinated debentures, at amortized cost	88,553,000		88,724,000
Derivatives	6,285,000		15,982,000
Carrying Value
FINANCIAL ASSETS:
Cash and cash equivalents	1,191,444,000		622,637,000
Equity and other investment securities	64,764,000		61,841,000
Investment securities available for sale	2,842,076,000		2,977,108,000
Investment securities held to maturity	3,320,000		3,606,000
Loans held for sale, at fair value	355,022,000		166,461,000
Loans and leases, net	21,364,506,000		20,277,795,000
Restricted equity securities	54,463,000		40,268,000
Residential mortgage servicing rights	151,383,000		169,025,000
Bank owned life insurance	318,533,000		313,626,000
Derivatives	200,412,000		49,484,000
Visa Inc. Class B common stock	0		0
FINANCIAL LIABILITIES:
Deposits	22,434,734,000		21,137,486,000
Securities sold under agreements to repurchase	296,717,000		297,151,000
Borrowings	1,106,674,000		751,788,000
Junior subordinated debentures, at fair value	267,798,000		300,870,000
Junior subordinated debentures, at amortized cost	88,553,000		88,724,000
Derivatives	6,285,000		15,982,000
Fair Value
FINANCIAL ASSETS:
Cash and cash equivalents	1,191,444,000		622,637,000
Equity and other investment securities	64,764,000		61,841,000
Investment securities available for sale	2,842,076,000		2,977,108,000
Investment securities held to maturity	4,338,000		4,644,000
Loans held for sale, at fair value	355,022,000		166,461,000
Loans and leases, net	21,566,083,000		20,117,939,000
Restricted equity securities	54,463,000		40,268,000
Residential mortgage servicing rights	151,383,000		169,025,000
Bank owned life insurance	318,533,000		313,626,000
Derivatives	200,412,000		49,484,000
Visa Inc. Class B common stock	0		99,353,000
FINANCIAL LIABILITIES:
Deposits	22,457,847,000		21,116,852,000
Securities sold under agreements to repurchase	296,717,000		297,151,000
Borrowings	1,105,167,000		738,107,000
Junior subordinated debentures, at fair value	267,798,000		300,870,000
Junior subordinated debentures, at amortized cost	69,511,000		76,569,000
Derivatives	$ 6,285,000		$ 15,982,000