Securities (Schedule of Information Regarding Securities with Unrealized Losses) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Securities in an Unrealized Loss Position for Less than 12 Months
Fair Value, AFS and HTM	$ 1,347,801	$ 555,070
Unrealized Losses, AFS and HTM	21,319	2,348
Securities in an Unrealized Loss Position for More than 12 Months
Fair Value, AFS and HTM	17,449	7,003
Unrealized Losses, AFS and HTM	342	332
Total
Fair Value, AFS and HTM	1,365,250	562,073
Unrealized Losses, AFS and HTM	21,661	2,680
Government-sponsored enterprise securities
Securities in an Unrealized Loss Position for Less than 12 Months
Fair Value, AFS	67,872	29,812
Unrealized Losses, AFS	2,143	181
Securities in an Unrealized Loss Position for More than 12 Months
Fair Value, AFS	0	0
Unrealized Losses, AFS	0	0
Total
Fair Value, AFS	67,872	29,812
Unrealized Losses, AFS	2,143	181
Mortgage-backed securities
Securities in an Unrealized Loss Position for Less than 12 Months
Fair Value, AFS and HTM	1,189,049	497,992
Unrealized Losses, AFS and HTM	16,975	1,957
Securities in an Unrealized Loss Position for More than 12 Months
Fair Value, AFS and HTM	12,596	6,168
Unrealized Losses, AFS and HTM	196	167
Total
Fair Value, AFS and HTM	1,201,645	504,160
Unrealized Losses, AFS and HTM	17,171	2,124
Corporate bonds
Securities in an Unrealized Loss Position for Less than 12 Months
Fair Value, AFS	0	3,956
Unrealized Losses, AFS	0	45
Securities in an Unrealized Loss Position for More than 12 Months
Fair Value, AFS	4,853	835
Unrealized Losses, AFS	146	165
Total
Fair Value, AFS	4,853	4,791
Unrealized Losses, AFS	146	210
State and local governments
Securities in an Unrealized Loss Position for Less than 12 Months
Fair Value, HTM	90,880	23,310
Unrealized Losses, HTM	2,201	165
Securities in an Unrealized Loss Position for More than 12 Months
Fair Value, HTM	0	0
Unrealized Losses, HTM	0	0
Total
Fair Value, HTM	90,880	23,310
Unrealized Losses, HTM	$ 2,201	$ 165

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