Loans - Change in the Balances of the ALLL (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Allowance for loan losses:
Balance, beginning of period	$ 15,560	$ 11,894	$ 14,970	$ 10,981
Provision (credit) charged to expense	667	1,322	1,517	2,357
Losses charged off	(254)	170	(560)	393
Recoveries	80	148	126	249
Balance, end of period	16,053	13,194	16,053	13,194
Commercial and industrial
Allowance for loan losses:
Balance, beginning of period	1,636	1,323	1,738	1,352
Provision (credit) charged to expense	(275)	205	(377)	132
Losses charged off	0	0	0	0
Recoveries	3	25	3	69
Balance, end of period	1,364	1,553	1,364	1,553
Owner-occupied commercial real estate
Allowance for loan losses:
Balance, beginning of period	861	635	803	582
Provision (credit) charged to expense	28	81	86	134
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	889	716	889	716
Investor commercial real estate
Allowance for loan losses:
Balance, beginning of period	71	101	85	168
Provision (credit) charged to expense	(4)	8	(18)	(59)
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	67	109	67	109
Construction
Allowance for loan losses:
Balance, beginning of period	367	462	423	544
Provision (credit) charged to expense	(72)	(67)	(128)	(149)
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	295	395	295	395
Single tenant lease financing
Allowance for loan losses:
Balance, beginning of period	8,093	6,853	7,872	6,248
Provision (credit) charged to expense	201	550	422	1,155
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	8,294	7,403	8,294	7,403
Public finance
Allowance for loan losses:
Balance, beginning of period	1,118	142	959	0
Provision (credit) charged to expense	254	220	413	362
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	1,372	362	1,372	362
Healthcare finance
Allowance for loan losses:
Balance, beginning of period	484		313
Provision (credit) charged to expense	192		363
Losses charged off	0		0
Recoveries	0		0
Balance, end of period	676		676
Residential mortgage
Allowance for loan losses:
Balance, beginning of period	984	904	956	754
Provision (credit) charged to expense	(77)	85	(41)	235
Losses charged off	0	0	(9)	0
Recoveries	2	2	3	2
Balance, end of period	909	991	909	991
Home equity
Allowance for loan losses:
Balance, beginning of period	58	101	70	102
Provision (credit) charged to expense	(7)	(38)	(23)	(42)
Losses charged off	0	0	0	0
Recoveries	3	17	7	20
Balance, end of period	54	80	54	80
Other consumer
Allowance for loan losses:
Balance, beginning of period	1,888	1,373	1,751	1,231
Provision (credit) charged to expense	427	278	820	589
Losses charged off	(254)	170	(551)	393
Recoveries	72	104	113	158
Balance, end of period	$ 2,133	$ 1,585	$ 2,133	$ 1,585