Fair Value Measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 2,572,721	$ 2,646,767
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	14,673	7,264
Estimated Fair Value	2,572,721	2,646,767
Investments held in Rabbi Trust	28,046	23,435
Derivative assets	174,626	167,468
Assets, Fair Value Disclosure	2,790,066	2,844,934
Liabilities Held-In-Trust, Fair Value Disclosure	28,046	23,435
Derivative Liability	291,499	297,049
Total liabilities	319,545	320,484
US Government Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	220,638	218,485
US Government Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	220,638	218,485
US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	999	1,008
US Government Agencies Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	999	1,008
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,053,908	1,105,712
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,053,908	1,105,712
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	424,379	422,309
Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	424,379	422,309
Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	120,458	134,033
Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	120,458	134,033
Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	204,888	212,698
Mortgage-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	204,888	212,698
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	547,451	552,522
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	547,451	552,522
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	0	0
Estimated Fair Value	220,638	218,485
Investments held in Rabbi Trust	28,046	23,435
Derivative assets	547	672
Assets, Fair Value Disclosure	249,231	242,592
Liabilities Held-In-Trust, Fair Value Disclosure	28,046	23,435
Derivative Liability	275	584
Total liabilities	28,321	24,019
Fair Value, Inputs, Level 1 [Member] | US Government Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	220,638	218,485
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 1 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	14,673	7,264
Estimated Fair Value	2,352,083	2,428,282
Investments held in Rabbi Trust	0	0
Derivative assets	174,079	166,796
Assets, Fair Value Disclosure	2,540,835	2,602,342
Liabilities Held-In-Trust, Fair Value Disclosure	0	0
Derivative Liability	291,224	296,465
Total liabilities	291,224	296,465
Fair Value, Inputs, Level 2 [Member] | US Government Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	999	1,008
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,053,908	1,105,712
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	424,379	422,309
Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	120,458	134,033
Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	204,888	212,698
Fair Value, Inputs, Level 2 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	547,451	552,522
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	0	0
Estimated Fair Value	0	0
Investments held in Rabbi Trust	0	0
Derivative assets	0	0
Assets, Fair Value Disclosure	0	0
Liabilities Held-In-Trust, Fair Value Disclosure	0	0
Derivative Liability	0	0
Total liabilities	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Fair Value, Inputs, Level 3 [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	$ 0	$ 0