Allowance for Loan and Lease Losses - Impaired Loans and Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Recorded Investment
Impaired loans with no related allowance recorded	$ 14,028		$ 14,028		$ 18,577
Impaired loans with a related allowance recorded	12,527		12,527		11,999
Total impaired loans	26,555		26,555		30,576
Unpaid Principal Balance
Impaired loans with no related allowance recorded	14,537		14,537		18,940
Impaired loans with a related allowance recorded	12,913		12,913		12,384
Total impaired loans	27,450		27,450		31,324
Related Allowance, Impaired loans	415		415		536
Average Recorded Investment
Impaired loans with no related allowance recorded	14,999	$ 28,690	15,592	$ 32,712
Impaired loans with a related allowance recorded	11,987	13,949	12,921	11,332
Total impaired loans	26,986	42,639	28,513	44,044
Interest Income Recognized
Impaired loans with no related allowance recorded	164	229	653	668
Impaired loans with a related allowance recorded	202	230	628	701
Total impaired loans	366	459	1,281	1,369
Commercial and Industrial
Recorded Investment
Impaired loans with no related allowance recorded	2,498		2,498		4,449
Impaired loans with a related allowance recorded	5,741		5,741		4,270
Total impaired loans	8,239		8,239		8,719
Unpaid Principal Balance
Impaired loans with no related allowance recorded	2,510		2,510		4,498
Impaired loans with a related allowance recorded	5,741		5,741		4,270
Total impaired loans	8,251		8,251		8,768
Related Allowance, Impaired loans	106		106		108
Average Recorded Investment
Impaired loans with no related allowance recorded	3,888	8,830	3,653	13,149
Impaired loans with a related allowance recorded	4,673	5,605	5,325	2,875
Total impaired loans	8,561	14,435	8,978	16,024
Interest Income Recognized
Impaired loans with no related allowance recorded	38	38	123	141
Impaired loans with a related allowance recorded	94	136	301	402
Total impaired loans	132	174	424	543
Commercial real estate
Recorded Investment
Impaired loans with no related allowance recorded	2,876		2,876		5,016
Impaired loans with a related allowance recorded	701		701		727
Total impaired loans	3,577		3,577		5,743
Unpaid Principal Balance
Impaired loans with no related allowance recorded	2,876		2,876		5,016
Impaired loans with a related allowance recorded	701		701		727
Total impaired loans	3,577		3,577		5,743
Related Allowance, Impaired loans	25		25		32
Average Recorded Investment
Impaired loans with no related allowance recorded	2,946	7,671	3,524	8,587
Impaired loans with a related allowance recorded	706	1,106	714	996
Total impaired loans	3,652	8,777	4,238	9,583
Interest Income Recognized
Impaired loans with no related allowance recorded	38	47	250	116
Impaired loans with a related allowance recorded	10	17	30	51
Total impaired loans	48	64	280	167
Construction
Average Recorded Investment
Impaired loans with no related allowance recorded		2,120		1,560
Total impaired loans		2,120		1,560
Interest Income Recognized
Impaired loans with no related allowance recorded		12		12
Total impaired loans		12		12
Residential mortgage
Recorded Investment
Impaired loans with no related allowance recorded	8,454		8,454		9,112
Impaired loans with a related allowance recorded	6,085		6,085		7,002
Total impaired loans	14,539		14,539		16,114
Unpaid Principal Balance
Impaired loans with no related allowance recorded	8,519		8,519		9,426
Impaired loans with a related allowance recorded	6,471		6,471		7,387
Total impaired loans	14,990		14,990		16,813
Related Allowance, Impaired loans	284		284		$ 396
Average Recorded Investment
Impaired loans with no related allowance recorded	8,065	10,069	8,365	9,416
Impaired loans with a related allowance recorded	6,608	7,238	6,882	7,461
Total impaired loans	14,673	17,307	15,247	16,877
Interest Income Recognized
Impaired loans with no related allowance recorded	88	132	280	399
Impaired loans with a related allowance recorded	98	77	297	248
Total impaired loans	186	$ 209	577	$ 647
Consumer
Recorded Investment
Impaired loans with no related allowance recorded	200		200
Total impaired loans	200		200
Unpaid Principal Balance
Impaired loans with no related allowance recorded	632		632
Total impaired loans	632		632
Average Recorded Investment
Impaired loans with no related allowance recorded	100		50
Total impaired loans	$ 100		$ 50