Loans Loans - Non-Accrual Loans, Segregated by Class of Loans and Year of Origination (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	$ 79,461	$ 102,303
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	27,146	26,038
Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	36,239	65,761
Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0	0
Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	12,154	8,912
Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	1,869	665
Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	2,035	922
Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	18	$ 5
Revolving Credit Facility [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	11,803
Revolving Credit Facility [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	8,163
Revolving Credit Facility [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	2,929
Revolving Credit Facility [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Revolving Credit Facility [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	357
Revolving Credit Facility [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Revolving Credit Facility [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	336
Revolving Credit Facility [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	18
Revolving Loans Converted to Term [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	9,778
Revolving Loans Converted to Term [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	4,039
Revolving Loans Converted to Term [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	5,682
Revolving Loans Converted to Term [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Revolving Loans Converted to Term [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Revolving Loans Converted to Term [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Revolving Loans Converted to Term [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	57
Revolving Loans Converted to Term [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2020 [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	30,508
2020 [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	1,439
2020 [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	27,628
2020 [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2020 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	249
2020 [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	1,192
2020 [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2020 [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2019 [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	9,391
2019 [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	2,951
2019 [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2019 [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2019 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	5,763
2019 [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	677
2019 [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2019 [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2018 [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	8,474
2018 [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	8,023
2018 [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2018 [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2018 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	33
2018 [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2018 [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	418
2018 [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2017 [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	3,734
2017 [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	2,130
2017 [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2017 [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2017 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	1,393
2017 [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2017 [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	211
2017 [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2016 [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	1,299
2016 [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	290
2016 [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2016 [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2016 [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	659
2016 [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
2016 [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	350
2016 [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Prior Years [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	4,474
Prior Years [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	111
Prior Years [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Prior Years [Member] | Paycheck Protection Program [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Prior Years [Member] | Commercial Real Estate Buildings Land And Other Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	3,700
Prior Years [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	0
Prior Years [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	663
Prior Years [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Non-accrual loans	$ 0