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, 2018	Dec. 31, 2017
Financial assets
Securities available for sale, at fair value	$ 1,177,606	$ 671,488
Loans held for sale	463,287	108,316
Mortgage servicing rights	46,413	39,339
Derivative instruments	772	0
Carrying Value
Financial assets
Cash and cash equivalents	369,596	281,453
Securities available for sale, at fair value	1,177,606	671,488
Loans held for sale	463,287	108,316
Loans, net	9,074,297	7,574,111
Mortgage servicing rights	46,413	39,339
Derivative instruments	11,116	5,977
Financial liabilities
Deposits	10,171,948	7,921,075
Short-term borrowings	175,559	89,814
Other long-term borrowings	61	98
Federal Home Loan Bank advances	6,887	7,493
Junior subordinated debentures	109,492	85,881
Subordinated notes	147,517	114,074
Derivative instruments	5,313	6,039
Fair Value
Financial assets
Cash and cash equivalents	369,596	281,453
Securities available for sale, at fair value	1,177,606	671,488
Loans held for sale	463,287	108,316
Loans, net	8,872,325	7,514,185
Mortgage servicing rights	61,655	47,868
Derivative instruments	11,116	5,977
Financial liabilities
Deposits	10,165,684	7,923,476
Short-term borrowings	175,559	89,814
Other long-term borrowings	61	98
Federal Home Loan Bank advances	6,906	7,661
Junior subordinated debentures	107,285	69,702
Subordinated notes	149,762	118,650
Derivative instruments	5,313	6,039
Fair Value \| Level 1
Financial assets
Cash and cash equivalents	369,596	281,453
Securities available for sale, at fair value	0	0
Loans held for sale	0	0
Loans, net	0	0
Mortgage servicing rights	0	0
Derivative instruments	0	0
Financial liabilities
Deposits	7,768,192	6,114,391
Short-term borrowings	175,559	89,814
Other long-term borrowings	61	98
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, at fair value	1,167,302	662,100
Loans held for sale	252,025	108,316
Loans, net	0	0
Mortgage servicing rights	0	0
Derivative instruments	11,116	5,977
Financial liabilities
Deposits	2,397,492	1,809,085
Short-term borrowings	0	0
Other long-term borrowings	0	0
Federal Home Loan Bank advances	6,906	7,661
Junior subordinated debentures	107,285	69,702
Subordinated notes	149,762	118,650
Derivative instruments	5,313	6,039
Fair Value \| Level 3
Financial assets
Cash and cash equivalents	0	0
Securities available for sale, at fair value	10,304	9,388
Loans held for sale	211,262	0
Loans, net	8,872,325	7,514,185
Mortgage servicing rights	61,655	47,868
Derivative instruments	0	0
Financial liabilities
Deposits	0	0
Short-term borrowings	0	0
Other long-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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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
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- Definition

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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- Definition

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.

+ References

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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- Definition

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 allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amount, after allowance for bad debt, of mortgage loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

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- Definition

The fair value amount of long-term debt 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.

+ References

No definition available.

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- Definition

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.

+ References

No definition available.

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