Securities - Amortized Cost and Fair Value, Available for Sale (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Line Items]
Amortized Cost	$ 2,400,956,000	$ 1,301,973,000
Gross Unrealized Gains	16,120,000	44,699,000
Gross Unrealized Losses	(31,024,000)	(3,215,000)
Fair Value	2,386,052,000	1,343,457,000
Amortized Cost	416,389,000	0
U.S. Treasury securities
Cash and Cash Equivalents [Line Items]
Amortized Cost	3,007,000	7,047,000
Gross Unrealized Gains	3,000	32,000
Gross Unrealized Losses	0	0
Fair Value	3,010,000	7,079,000
Obligations of other U.S. Government agencies and corporations
Cash and Cash Equivalents [Line Items]
Amortized Cost		1,003,000
Gross Unrealized Gains		6,000
Gross Unrealized Losses		0
Fair Value		1,009,000
Obligations of states and political subdivisions
Cash and Cash Equivalents [Line Items]
Amortized Cost	153,847,000	291,231,000
Gross Unrealized Gains	5,532,000	14,015,000
Gross Unrealized Losses	(269,000)	(45,000)
Fair Value	159,110,000	305,201,000
Amortized Cost	267,641,000
Residential mortgage backed securities:
Cash and Cash Equivalents [Line Items]
Amortized Cost	24,832,000
Trust preferred securities
Cash and Cash Equivalents [Line Items]
Amortized Cost		12,013,000
Gross Unrealized Gains		0
Gross Unrealized Losses		(3,001,000)
Fair Value		9,012,000
Other debt securities
Cash and Cash Equivalents [Line Items]
Amortized Cost	36,515,000	62,771,000
Gross Unrealized Gains	1,097,000	2,909,000
Gross Unrealized Losses	(148,000)	(73,000)
Fair Value	37,464,000	65,607,000
Amortized Cost	22,049,000
Government agency mortgage backed securities | Residential mortgage backed securities:
Cash and Cash Equivalents [Line Items]
Amortized Cost	967,497,000	581,105,000
Gross Unrealized Gains	7,854,000	21,564,000
Gross Unrealized Losses	(6,816,000)	(23,000)
Fair Value	968,535,000	602,646,000
Amortized Cost	60,507,000
Government agency mortgage backed securities | Commercial mortgage backed securities:
Cash and Cash Equivalents [Line Items]
Amortized Cost	14,717,000	29,053,000
Gross Unrealized Gains	365,000	1,235,000
Gross Unrealized Losses	(1,000)	(1,000)
Fair Value	15,081,000	30,287,000
Amortized Cost	1,855,000
Government agency collateralized mortgage obligations | Residential mortgage backed securities:
Cash and Cash Equivalents [Line Items]
Amortized Cost	1,008,514,000	218,373,000
Gross Unrealized Gains	457,000	1,946,000
Gross Unrealized Losses	(20,371,000)	(51,000)
Fair Value	988,600,000	220,268,000
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Cash and Cash Equivalents [Line Items]
Amortized Cost	216,859,000	99,377,000
Gross Unrealized Gains	812,000	2,992,000
Gross Unrealized Losses	(3,419,000)	(21,000)
Fair Value	214,252,000	$ 102,348,000
Amortized Cost	$ 39,505,000