Allowance for Loan and Lease Losses - Impaired Loans and Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Recorded Investment
Impaired loans with no related allowance recorded	$ 15,969		$ 15,969		$ 18,577
Impaired loans with a related allowance recorded	11,444		11,444		11,999
Total impaired loans	27,413		27,413		30,576
Unpaid Principal Balance
Impaired loans with no related allowance recorded	16,161		16,161		18,940
Impaired loans with a related allowance recorded	11,830		11,830		12,384
Total impaired loans	27,991		27,991		31,324
Related Allowance, Impaired loans	500		500		536
Average Recorded Investment
Impaired loans with no related allowance recorded	14,883	$ 36,554	16,114	$ 36,513
Impaired loans with a related allowance recorded	13,580	9,083	13,053	9,028
Total impaired loans	28,463	45,637	29,167	45,541
Interest Income Recognized
Impaired loans with no related allowance recorded	226	353	578	704
Impaired loans with a related allowance recorded	174	141	336	252
Total impaired loans	400	494	914	956
Commercial and Industrial
Recorded Investment
Impaired loans with no related allowance recorded	5,278		5,278		4,449
Impaired loans with a related allowance recorded	3,604		3,604		4,270
Total impaired loans	8,882		8,882		8,719
Unpaid Principal Balance
Impaired loans with no related allowance recorded	5,311		5,311		4,498
Impaired loans with a related allowance recorded	3,604		3,604		4,270
Total impaired loans	8,915		8,915		8,768
Related Allowance, Impaired loans	108		108		108
Average Recorded Investment
Impaired loans with no related allowance recorded	3,833	15,815	4,038	16,556
Impaired loans with a related allowance recorded	5,645	749	5,187	548
Total impaired loans	9,478	16,564	9,225	17,104
Interest Income Recognized
Impaired loans with no related allowance recorded	94	171	175	337
Impaired loans with a related allowance recorded	61	18	117	35
Total impaired loans	155	189	292	372
Commercial Real Estate
Recorded Investment
Impaired loans with no related allowance recorded	3,016		3,016		5,016
Impaired loans with a related allowance recorded	710		710		727
Total impaired loans	3,726		3,726		5,743
Unpaid Principal Balance
Impaired loans with no related allowance recorded	3,016		3,016		5,016
Impaired loans with a related allowance recorded	710		710		727
Total impaired loans	3,726		3,726		5,743
Related Allowance, Impaired loans	25		25		32
Average Recorded Investment
Impaired loans with no related allowance recorded	3,102	9,144	3,740	9,345
Impaired loans with a related allowance recorded	715	878	719	882
Total impaired loans	3,817	10,022	4,459	10,227
Interest Income Recognized
Impaired loans with no related allowance recorded	40	72	212	127
Impaired loans with a related allowance recorded	10	10	20	20
Total impaired loans	50	82	232	147
Construction
Average Recorded Investment
Impaired loans with no related allowance recorded		2,120		1,413
Total impaired loans		2,120		1,413
Residential mortgage
Recorded Investment
Impaired loans with no related allowance recorded	7,675		7,675		9,112
Impaired loans with a related allowance recorded	7,130		7,130		7,002
Total impaired loans	14,805		14,805		16,114
Unpaid Principal Balance
Impaired loans with no related allowance recorded	7,834		7,834		9,426
Impaired loans with a related allowance recorded	7,516		7,516		7,387
Total impaired loans	15,350		15,350		16,813
Related Allowance, Impaired loans	367		367		$ 396
Average Recorded Investment
Impaired loans with no related allowance recorded	7,948	9,475	8,336	9,199
Impaired loans with a related allowance recorded	7,220	7,456	7,147	7,598
Total impaired loans	15,168	16,931	15,483	16,797
Interest Income Recognized
Impaired loans with no related allowance recorded	92	110	191	240
Impaired loans with a related allowance recorded	103	113	199	197
Total impaired loans	$ 195	$ 223	$ 390	$ 437