Securities - Available for Sale Securities With Gross Unrealized Losses and Their Fair Value (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Held-to-maturity securities have been in a continuous unrealized loss position, number of positions	1
Held-to-maturity securities have been in a continuous unrealized loss position, fair value	$ 20,819
Held-to-maturity securities have been in a continuous unrealized loss position, unrealized loss	157
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, fair value	20,819
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	157
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, fair value	0
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0
Securities have been in a continuous unrealized loss position, number of positions	61	37
Securities have been in a continuous unrealized loss position, fair value	$ 486,946	$ 290,820
Securities have been in a continuous unrealized loss position, unrealized losses	8,006	7,766
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	436,825	76,729
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	6,861	186
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	50,121	214,091
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 1,145	$ 7,580
US States and Political Subdivisions Debt Securities [Member]
Held-to-maturity securities have been in a continuous unrealized loss position, number of positions	1
Held-to-maturity securities have been in a continuous unrealized loss position, fair value	$ 20,819
Held-to-maturity securities have been in a continuous unrealized loss position, unrealized loss	157
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, fair value	20,819
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	157
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, fair value	0
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0
US Government Agencies Debt Securities [Member]
Securities have been in a continuous unrealized loss position, number of positions	1	1
Securities have been in a continuous unrealized loss position, fair value	$ 4,489	$ 4,988
Securities have been in a continuous unrealized loss position, unrealized losses	3	1
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	4,489	4,988
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	3	1
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0	0
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0	$ 0
Corporate Debt Securities [Member]
Securities have been in a continuous unrealized loss position, number of positions	11	14
Securities have been in a continuous unrealized loss position, fair value	$ 80,792	$ 113,734
Securities have been in a continuous unrealized loss position, unrealized losses	1,654	6,266
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	51,698	0
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	748	0
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	29,094	113,734
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 906	$ 6,266
Collateralized Loan Obligations [Member]
Securities have been in a continuous unrealized loss position, number of positions	3	13
Securities have been in a continuous unrealized loss position, fair value	$ 21,027	$ 99,199
Securities have been in a continuous unrealized loss position, unrealized losses	239	1,363
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	0	7,441
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	0	52
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	21,027	91,758
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 239	$ 1,311
Other Debt Obligations [Member]
Held-to-maturity securities have been in a continuous unrealized loss position, number of positions	1
Held-to-maturity securities have been in a continuous unrealized loss position, fair value	$ 20,819
Held-to-maturity securities have been in a continuous unrealized loss position, unrealized loss	157
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, fair value	20,819
Held-to-maturity securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	157
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, fair value	0
Held-to-maturity securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0
Securities have been in a continuous unrealized loss position, number of positions	15	28
Securities have been in a continuous unrealized loss position, fair value	$ 106,308	$ 217,921
Securities have been in a continuous unrealized loss position, unrealized losses	1,896	7,630
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	56,187	12,429
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	751	53
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	50,121	205,492
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 1,145	$ 7,577
Collateralized Mortgage Backed Securities [Member]
Securities have been in a continuous unrealized loss position, number of positions	46	9
Securities have been in a continuous unrealized loss position, fair value	$ 380,638	$ 72,899
Securities have been in a continuous unrealized loss position, unrealized losses	6,110	136
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	380,638	64,300
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	6,110	133
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0	8,599
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0	$ 3
REMIC and CMO [Member]
Securities have been in a continuous unrealized loss position, number of positions	12
Securities have been in a continuous unrealized loss position, fair value	$ 110,359
Securities have been in a continuous unrealized loss position, unrealized losses	1,981
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	110,359
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	1,981
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0
GNMA [Member]
Securities have been in a continuous unrealized loss position, number of positions	2	1
Securities have been in a continuous unrealized loss position, fair value	$ 10,196	$ 10,341
Securities have been in a continuous unrealized loss position, unrealized losses	312	22
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	10,196	10,341
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	312	22
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0	0
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0	$ 0
FNMA [Member]
Securities have been in a continuous unrealized loss position, number of positions	17	5
Securities have been in a continuous unrealized loss position, fair value	$ 136,324	$ 32,463
Securities have been in a continuous unrealized loss position, unrealized losses	1,758	31
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	136,324	23,864
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	1,758	28
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0	8,599
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0	$ 3
FHLMC [Member]
Securities have been in a continuous unrealized loss position, number of positions	15	3
Securities have been in a continuous unrealized loss position, fair value	$ 123,759	$ 30,095
Securities have been in a continuous unrealized loss position, unrealized losses	2,059	83
Securities have been in a continuous unrealized loss position, less than 12 months, fair value	123,759	30,095
Securities have been in a continuous unrealized loss position, less than 12 months, unrealized losses	2,059	83
Securities have been in a continuous unrealized loss position, 12 months or more, fair value	0	0
Securities have been in a continuous unrealized loss position, 12 months or more, unrealized losses	$ 0	$ 0