Estimated Fair Values (Assets And Liabilities Carried At Fair Value On A Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate remeasured during current year	$ 60,781		$ 61,231	$ 67,089		$ 65,559
Other Real Estate, Non Covered	60,619		60,759	66,605		58,742
Other Real Estate, Covered	162		472	484		6,817
Mortgage servicing rights	20,524	$ 20,771	20,415	$ 16,824	$ 17,186	$ 19,351
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	74,373		70,977
Other real estate remeasured during current year	32,703		45,402
Mortgage servicing rights			342
Fair Value, Measurements, Nonrecurring | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0		0
Other real estate remeasured during current year	0		0
Mortgage servicing rights			0
Fair Value, Measurements, Nonrecurring | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0		0
Other real estate remeasured during current year	0		0
Mortgage servicing rights			0
Fair Value, Measurements, Nonrecurring | Significant Unobservable Inputs (Level 3 Inputs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	74,373		70,977
Other real estate remeasured during current year	$ 32,703		45,402
Mortgage servicing rights			$ 342