Securities Securities (Available for sale securities in continuous unrealized loss position) (Details) $ in Thousands	Sep. 30, 2021 USD ($) holding	Dec. 31, 2020 USD ($) holding
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	32	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,062,806	$ 24,248
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(10,078)	(89)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,314	1,056
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(332)	(373)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,064,120	25,304
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 10,410	$ 462
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	9	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 131,548	$ 437
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(3,287)	(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	304	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	131,852	437
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 3,288	$ 1
Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	1	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 22,994	$ 23,323
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(522)	(87)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	22,994	23,323
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 522	$ 87
Single issuer trust preferred securities issued by banks and insurers
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding		1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		$ 488
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		488
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		$ 1
Pooled trust preferred securities issued by banks and insurers
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	1	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 0	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,010	1,056
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(331)	(373)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,010	1,056
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 331	$ 373
U.S. government agency securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 138,262
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,779)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Available-for-sale, Unrealized Loss Position	138,262
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 1,779
US Treasury Securities [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| holding	16
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 770,002
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(4,490)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Available-for-sale, Unrealized Loss Position	770,002
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 4,490

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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