Purchased Loans - Narrative (Details)	3 Months Ended
Mar. 31, 2019 USD ($) loan	Mar. 31, 2018 USD ($) loan	Dec. 31, 2018 USD ($)
Loans and Allowance for Loan Losses (Textual) [Abstract]
Allowance for loan losses attributable to restructured loans	$ 49,835,000		$ 49,026,000
Purchased loans
Loans and Allowance for Loan Losses (Textual) [Abstract]
Number of Loans \| loan	0	2
Modifications with subsequent default		$ 0
Number of restructured loans \| loan	4	0
Restructured loans discontinued past due period	90 days	90 days
Remaining availability under commitments to lend additional funds on restructured loans	$ 3,000	$ 2,000
Purchased loans \| Nonaccruing Loans
Loans and Allowance for Loan Losses (Textual) [Abstract]
Outstanding balance of restructured loans	414,000
Purchased loans \| Restructured Loans
Loans and Allowance for Loan Losses (Textual) [Abstract]
Outstanding balance of restructured loans	1,851,000	616,000
Allowance for loan losses attributable to restructured loans	$ 86,000	$ 100,000

Loans and the allowance for loan losses.

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Number of Restructured Loans

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Maximum duration past due for restructured loans to be considered performing.

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Number of financing receivables that have been modified by troubled debt restructurings.

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

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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. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

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