Fair Value Measurements (Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands		Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Values, Assets		$ 72,408	$ 6,908
Fair Values, Liabilities		3,102	22,244
Total recurring fair value measurements - liabilities		3,100	4,100
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		5,779,381	6,986,698
Mortgage loans held for sale		21,496	41,022
Fair Values, Assets	[1]	78,793	75,867
Total fair value measurements		5,879,670	7,103,587
Fair Values, Liabilities	[1]	118,652	35,046
Total recurring fair value measurements - liabilities		118,652	35,046
Recurring [Member] | U.S. Treasury And Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		9,064	419,298
Recurring [Member] | Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		210,744	314,158
Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		22,377	18,702
Recurring [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		2,533,035	3,035,798
Recurring [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		2,921,123	3,077,859
Recurring [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		83,038	120,883
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		5,779,381	6,986,698
Mortgage loans held for sale		21,496	41,022
Fair Values, Assets	[1]	78,793	75,867
Total fair value measurements		5,879,670	7,103,587
Fair Values, Liabilities	[1]	115,541	30,930
Total recurring fair value measurements - liabilities		115,541	30,930
Recurring [Member] | Level 2 [Member] | U.S. Treasury And Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		9,064	419,298
Recurring [Member] | Level 2 [Member] | Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		210,744	314,158
Recurring [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		22,377	18,702
Recurring [Member] | Level 2 [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		2,533,035	3,035,798
Recurring [Member] | Level 2 [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		2,921,123	3,077,859
Recurring [Member] | Level 2 [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		83,038	120,883
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Values, Liabilities	[1]	3,111	4,116
Total recurring fair value measurements - liabilities		$ 3,111	$ 4,116

[1] For further disaggregation of derivative assets and liabilities, see Note 5 - Derivatives.