Fair Value Measurement (Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	$ 62,454		$ 62,454			$ 12,255
Available for sale, at fair value	2,864,394		2,864,394			3,065,769
Loans held for sale, at fair value	289,537		289,537			259,518
Residential mortgage servicing rights, at fair value	175,038	$ 141,225	175,038	$ 141,225	$ 166,217	153,151	$ 141,832	$ 142,973
Derivatives, assets	18,718		18,718			32,256
Total assets measured at fair value	3,410,141		3,410,141			3,522,949
Junior subordinated debentures, at fair value	282,846		282,846			277,155
Derivatives, liabilities	39,893		39,893			9,288
Total liabilities measured at fair value	322,739		322,739			286,443
Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	719		719			1,137
Derivatives, liabilities	513		513			1,492
Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	50,065		50,065
Available for sale, at fair value						51,970
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	12,241		12,241			11,982
Other Investment Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	148		148
U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	39,469		39,469			39,698
Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value						273
Available for sale, at fair value	294,664		294,664			308,456
Residential mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,530,261		2,530,261			2,665,645
Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	5,159		5,159			4,752
Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,950		1,950			286
Derivatives, liabilities	77		77			567
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,890		10,890			26,081
Derivatives, liabilities	39,303		39,303			7,229
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	0		0			0
Residential mortgage servicing rights, at fair value	0		0			0
Total assets measured at fair value	62,306		62,306			63,952
Junior subordinated debentures, at fair value	0		0			0
Total liabilities measured at fair value	0		0			0
Level 1 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	0		0			0
Level 1 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	50,065		50,065
Available for sale, at fair value						51,970
Level 1 | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	12,241		12,241			11,982
Level 1 | Other Investment Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0
Level 1 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0		0			0
Level 1 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value						0
Available for sale, at fair value	0		0			0
Level 1 | Residential mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0		0			0
Level 1 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Level 1 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	0		0			0
Level 1 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	0		0			0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	289,537		289,537			259,518
Residential mortgage servicing rights, at fair value	0		0			0
Total assets measured at fair value	3,167,638		3,167,638			3,301,094
Junior subordinated debentures, at fair value	0		0			0
Total liabilities measured at fair value	39,893		39,893			9,288
Level 2 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	719		719			1,137
Derivatives, liabilities	513		513			1,492
Level 2 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0
Available for sale, at fair value
Level 2 | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0			0
Level 2 | Other Investment Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	148		148
Level 2 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	39,469		39,469			39,698
Level 2 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value						273
Available for sale, at fair value	294,664		294,664			308,456
Level 2 | Residential mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	2,530,261		2,530,261			2,665,645
Level 2 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Level 2 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,950		1,950			286
Derivatives, liabilities	77		77			567
Level 2 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	10,890		10,890			26,081
Derivatives, liabilities	39,303		39,303			7,229
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	0		0			0
Residential mortgage servicing rights, at fair value	175,038		175,038			153,151
Total assets measured at fair value	180,197		180,197			157,903
Junior subordinated debentures, at fair value	282,846		282,846			277,155
Total liabilities measured at fair value	282,846		282,846			277,155
Level 3 | Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	0		0			0
Level 3 | Investments in mutual funds and other securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0
Available for sale, at fair value						0
Level 3 | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0			0
Level 3 | Other Investment Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value	0		0
Level 3 | U.S. Treasury and agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0		0			0
Level 3 | Obligations of states and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity and other, at fair value						0
Available for sale, at fair value	0		0			0
Level 3 | Residential mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale, at fair value	0		0			0
Level 3 | Interest Rate Lock Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	5,159	4,781	5,159	4,781	$ 6,782	4,752	$ 4,746	$ 4,076
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	5,159	$ 4,781	5,159	$ 4,781
Derivatives, assets	5,159		5,159			4,752
Level 3 | Interest Rate Forward Sales Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	0		0			0
Level 3 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	0		0			0
Derivatives, liabilities	$ 0		$ 0			$ 0