Fair Value Measurements (Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 127,529	$ 110,734
Derivative liabilities		122,171	32,601
Total recurring fair value measurements - liabilities		1,400	1,900
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		5,188,156	5,556,041
Mortgage loans held for sale		13,298	10,843
Derivative assets	[1]	124,431	109,497
Total fair value measurements		5,325,885	5,676,381
Derivative liabilities	[1]	307,669	204,121
Total recurring fair value measurements - liabilities		307,669	204,121
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		114,190	110,865
Recurring [Member] | Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		193,111	203,092
Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		20,107	21,080
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		1,960,567	2,256,986
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		2,841,351	2,893,430
Recurring [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		58,830	70,588
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		5,188,156	5,556,041
Mortgage loans held for sale		13,298	10,843
Derivative assets	[1]	124,431	109,497
Total fair value measurements		5,325,885	5,676,381
Derivative liabilities	[1]	306,237	202,238
Total recurring fair value measurements - liabilities		306,237	202,238
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		114,190	110,865
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		193,111	203,092
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		20,107	21,080
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		1,960,567	2,256,986
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		2,841,351	2,893,430
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		58,830	70,588
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	[1]	1,432	1,883
Total recurring fair value measurements - liabilities		$ 1,432	$ 1,883

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