Fair Value Measurements (Details 2) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair value measurements
Investment securities available-for-sale	$ 1,583,240	$ 1,197,467
Assets:
Mortgages held for sale	34,594	12,885
U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	893,672	619,482
U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	94,550	81,127
Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	571,150	453,789
Corporate debt securities
Fair value measurements
Investment securities available-for-sale	23,268	42,369
Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	600	700
Total
Fair value measurements
Investment securities available-for-sale	1,583,240	1,197,467
Assets:
Mortgages held for sale	34,594	12,885
Level 1
Fair value measurements
Investment securities available-for-sale	372,074	80,285
Assets:
Mortgages held for sale	0	0
Level 2
Fair value measurements
Investment securities available-for-sale	1,209,337	1,115,030
Assets:
Mortgages held for sale	34,594	12,885
Level 3
Fair value measurements
Investment securities available-for-sale	1,829	2,152
Assets:
Mortgages held for sale	0	0
Recurring basis \| Total
Fair value measurements
Investment securities available-for-sale	1,583,240	1,197,467
Assets:
Mortgages held for sale	34,594	12,885
Total	1,646,202	1,257,006
Liabilities:
Total	28,975	47,681
Recurring basis \| Total \| Interest rate swap contracts
Assets:
Accrued income and other assets	28,368	46,654
Liabilities:
Accrued expenses and other liabilities	28,975	47,681
Recurring basis \| Total \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	893,672	619,482
Recurring basis \| Total \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	94,550	81,127
Recurring basis \| Total \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	571,150	453,789
Recurring basis \| Total \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	23,268	42,369
Recurring basis \| Total \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	600	700
Recurring basis \| Level 1
Fair value measurements
Investment securities available-for-sale	372,074	80,285
Assets:
Mortgages held for sale	0	0
Total	372,074	80,285
Liabilities:
Total	0	0
Recurring basis \| Level 1 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis \| Level 1 \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	372,074	80,285
Recurring basis \| Level 1 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 1 \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 2
Fair value measurements
Investment securities available-for-sale	1,209,337	1,115,030
Assets:
Mortgages held for sale	34,594	12,885
Total	1,272,299	1,174,569
Liabilities:
Total	28,975	47,681
Recurring basis \| Level 2 \| Interest rate swap contracts
Assets:
Accrued income and other assets	28,368	46,654
Liabilities:
Accrued expenses and other liabilities	28,975	47,681
Recurring basis \| Level 2 \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	521,598	539,197
Recurring basis \| Level 2 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	92,721	78,975
Recurring basis \| Level 2 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	571,150	453,789
Recurring basis \| Level 2 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	23,268	42,369
Recurring basis \| Level 2 \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	600	700
Recurring basis \| Level 3
Fair value measurements
Investment securities available-for-sale	1,829	2,152
Assets:
Mortgages held for sale	0	0
Total	1,829	2,152
Liabilities:
Total	0	0
Recurring basis \| Level 3 \| Interest rate swap contracts
Assets:
Accrued income and other assets	0	0
Liabilities:
Accrued expenses and other liabilities	0	0
Recurring basis \| Level 3 \| U.S. Treasury and Federal agencies securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| U.S. States and political subdivisions securities
Fair value measurements
Investment securities available-for-sale	1,829	2,152
Recurring basis \| Level 3 \| Mortgage-backed securities - Federal agencies
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| Corporate debt securities
Fair value measurements
Investment securities available-for-sale	0	0
Recurring basis \| Level 3 \| Foreign government and other securities
Fair value measurements
Investment securities available-for-sale	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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