Fair Value Measurements - Assets and Liabilities Not Measured and Reported at Fair Value on a Recurring Basis or Nonrecurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial assets
Securities available for sale	$ 2,544,643	$ 1,343,457
Loans held for sale	452,869	417,771
Loans, net	9,846,786	10,757,503
Mortgage servicing rights	86,387	62,994
Derivative instruments	15,373	3,866
Financial liabilities
Derivative instruments	14,021	21,107
Carrying Value
Financial assets
Cash and cash equivalents	1,476,141	633,203
Securities available for sale	2,544,643	1,343,457
Loans held for sale	452,869	417,771
Loans, net	9,846,786	10,757,503
Mortgage servicing rights	86,387	62,994
Derivative instruments	28,134	33,574
Financial liabilities
Deposits	13,254,829	12,059,081
Short-term borrowings	11,253	21,340
Federal Home Loan Bank advances	150,425	152,167
Junior subordinated debentures	111,228	110,794
Subordinated notes	207,210	212,009
Derivative instruments	14,543	21,107
Fair Value
Financial assets
Cash and cash equivalents	1,476,141	633,203
Securities available for sale	2,544,643	1,343,457
Loans held for sale	452,869	417,771
Loans, net	9,726,732	10,668,625
Mortgage servicing rights	90,738	62,994
Derivative instruments	28,134	33,574
Financial liabilities
Deposits	13,255,301	12,069,198
Short-term borrowings	11,253	21,340
Federal Home Loan Bank advances	155,832	158,914
Junior subordinated debentures	105,546	93,092
Subordinated notes	221,700	217,575
Derivative instruments	14,543	21,107
Fair Value \| Level 1
Financial assets
Cash and cash equivalents	1,476,141	633,203
Securities available for sale	0	0
Loans held for sale	0	0
Loans, net	0	0
Mortgage servicing rights	0	0
Derivative instruments	0	0
Financial liabilities
Deposits	11,787,346	10,363,193
Short-term borrowings	11,253	21,340
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Subordinated notes	0	0
Derivative instruments	0	0
Fair Value \| Level 2
Financial assets
Cash and cash equivalents	0	0
Securities available for sale	2,544,643	1,334,445
Loans held for sale	452,869	417,771
Loans, net	0	0
Mortgage servicing rights	0	0
Derivative instruments	28,134	33,574
Financial liabilities
Deposits	1,467,955	1,706,005
Short-term borrowings	0	0
Federal Home Loan Bank advances	155,832	158,914
Junior subordinated debentures	105,546	93,092
Subordinated notes	221,700	217,575
Derivative instruments	14,543	21,107
Fair Value \| Level 3
Financial assets
Cash and cash equivalents	0	0
Securities available for sale	0	9,012
Loans held for sale	0	0
Loans, net	9,726,732	10,668,625
Mortgage servicing rights	90,738	62,994
Derivative instruments	0	0
Financial liabilities
Deposits	0	0
Short-term borrowings	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Subordinated notes	0	0
Derivative instruments	$ 0	$ 0

Junior Subordinated Debt Obligations, Fair Value Disclosure

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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).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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No definition available.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

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Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

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