Loans and Allowance for Loan Losses - Allowance For Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Allowance for loan losses
Balance, beginning of period	$ 6,865	$ 5,902	$ 6,250	$ 5,422
Provision for loan losses	592	240	1,072	720
Transfer out		(132)		(132)
Recoveries of loans previously charged off			135
Balance, end of period	7,457	6,010	7,457	6,010
Ending balance: individually evaluated for impairment	16		16		$ 41
Ending balance: collectively evaluated for impairment	7,441		7,441		6,209
Loans
Ending balance	1,209,152		1,209,152		941,796
Ending balance individually evaluated for impairment	3,471		3,471		5,568
Ending balance: collectively evaluated for impairment	1,205,681		1,205,681		936,228
Mortgage warehouse lines of credit
Allowance for loan losses
Balance, beginning of period	281	770	373	704
Provision for loan losses	(8)	(256)	(100)	(190)
Balance, end of period	273	514	273	514
Ending balance: collectively evaluated for impairment	273		273		373
Loans
Ending balance	233,466		233,466		275,039
Ending balance: collectively evaluated for impairment	233,466		233,466		275,039
Residential real estate
Allowance for loan losses
Balance, beginning of period	1,938	1,839	2,170	2,212
Provision for loan losses	(414)	18	(646)	(355)
Transfer out		(132)		(132)
Balance, end of period	1,524	1,725	1,524	1,725
Ending balance: individually evaluated for impairment					30
Ending balance: collectively evaluated for impairment	1,524		1,524		2,140
Loans
Ending balance	307,643		307,643		235,759
Ending balance individually evaluated for impairment	207		207		343
Ending balance: collectively evaluated for impairment	307,436		307,436		235,416
Multi-family and healthcare financing
Allowance for loan losses
Balance, beginning of period	2,426	1,737	1,962	1,308
Provision for loan losses	276	159	740	588
Balance, end of period	2,702	1,896	2,702	1,896
Ending balance: collectively evaluated for impairment	2,702		2,702		1,962
Loans
Ending balance	393,581		393,581		261,031
Ending balance: collectively evaluated for impairment	393,581		393,581		261,031
Commercial and commercial real estate
Allowance for loan losses
Balance, beginning of period	1,845	1,243	1,374	908
Provision for loan losses	688	284	1,058	619
Recoveries of loans previously charged off			101
Balance, end of period	2,533	1,527	2,533	1,527
Ending balance: collectively evaluated for impairment	2,533		2,533		1,374
Loans
Ending balance	210,421		210,421		113,812
Ending balance individually evaluated for impairment	2,982		2,982		5,022
Ending balance: collectively evaluated for impairment	207,439		207,439		108,790
Agricultural production and real estate
Allowance for loan losses
Balance, beginning of period	271	223	269	222
Provision for loan losses	36	21	38	22
Balance, end of period	307	244	307	244
Ending balance: individually evaluated for impairment	16		16		11
Ending balance: collectively evaluated for impairment	291		291		258
Loans
Ending balance	51,925		51,925		46,763
Ending balance individually evaluated for impairment	282		282		203
Ending balance: collectively evaluated for impairment	51,643		51,643		46,560
Consumer and margin loans
Allowance for loan losses
Balance, beginning of period	104	90	102	68
Provision for loan losses	14	14	(18)	36
Recoveries of loans previously charged off			34
Balance, end of period	118	$ 104	118	$ 104
Ending balance: collectively evaluated for impairment	118		118		102
Loans
Ending balance	12,116		12,116		9,392
Ending balance: collectively evaluated for impairment	$ 12,116		$ 12,116		$ 9,392

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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- Definition

Amount of other addition (reduction) in allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The balance of financing receivables that were collectively evaluated for impairment.

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- Definition

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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Amount before allowance and after 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.

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Amount of expense related to estimated loss from loan and lease transactions.

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