Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 18,971	$ 15,357
Derivative Assets	10,621	10,457
Derivative Liabilities	10,348	10,948
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	7,852	0
U.S. government and federal agency obligations	434,866	501,407
Government-sponsored enterprise obligations	886,501	963,127
State and municipal obligations	1,817,101	1,813,201
Agency mortgage-backed securities	2,587,693	2,593,708
Non-agency mortgage-backed securities	690,938	382,744
Other asset-backed securities	2,498,506	3,091,993
Other debt securities	265,107	139,161
Equity securities	41,109	38,219
Trading securities	18,971	15,357
Private equity investments	58,726	57,581
Derivative Assets	10,621	10,457
Assets held in trust	9,375	8,848
Total Assets	9,327,366	9,615,803
Derivative Liabilities	10,348	10,948
Total Liabilities	10,348	10,948
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	0	0
U.S. government and federal agency obligations	434,866	501,407
Government-sponsored enterprise obligations	0	0
State and municipal obligations	0	0
Agency mortgage-backed securities	0	0
Non-agency mortgage-backed securities	0	0
Other asset-backed securities	0	0
Other debt securities	0	0
Equity securities	20,272	17,975
Trading securities	0	0
Private equity investments	0	0
Derivative Assets	0	0
Assets held in trust	9,375	8,848
Total Assets	464,513	528,230
Derivative Liabilities	0	0
Total Liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	7,852	0
U.S. government and federal agency obligations	0	0
Government-sponsored enterprise obligations	886,501	963,127
State and municipal obligations	1,724,161	1,718,058
Agency mortgage-backed securities	2,587,693	2,593,708
Non-agency mortgage-backed securities	690,938	382,744
Other asset-backed securities	2,498,506	3,091,993
Other debt securities	265,107	139,161
Equity securities	20,837	20,244
Trading securities	18,971	15,357
Private equity investments	0	0
Derivative Assets	10,266	10,454
Assets held in trust	0	0
Total Assets	8,710,832	8,934,846
Derivative Liabilities	10,163	10,722
Total Liabilities	10,163	10,722
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	0	0
U.S. government and federal agency obligations	0	0
Government-sponsored enterprise obligations	0	0
State and municipal obligations	92,940	95,143
Agency mortgage-backed securities	0	0
Non-agency mortgage-backed securities	0	0
Other asset-backed securities	0	0
Other debt securities	0	0
Equity securities	0	0
Trading securities	0	0
Private equity investments	58,726	57,581
Derivative Assets	355	3
Assets held in trust	0	0
Total Assets	152,021	152,727
Derivative Liabilities	185	226
Total Liabilities	$ 185	$ 226