Loans and Allowance for Credit Losses - Summary of Impaired Loans (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]	$ 22,251	$ 21,590
Unpaid Principal Balance, With no related allowance for credit losses		35,443	30,508
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses		20,713	15,298
Undisbursed Commitments, With no related allowance for credit losses		3,658	387
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	56,953	52,020
Unpaid Principal Balance, With allowance for credit losses recorded		58,374	55,800
Related Specific Allowance, With allowance for credit losses recorded		7,432	8,522
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		50,870	28,060
Undisbursed Commitments, With allowance for credit losses recorded		3,269	2,902
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]	20,713	19,832
Unpaid Principal Balance, With no related allowance for credit losses		33,908	28,301
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses		20,713	15,014
Undisbursed Commitments, With no related allowance for credit losses		3,658	387
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	56,223	50,874
Unpaid Principal Balance, With allowance for credit losses recorded		56,871	54,385
Related Specific Allowance, With allowance for credit losses recorded		7,300	8,459
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		50,641	28,000
Undisbursed Commitments, With allowance for credit losses recorded		3,259	2,902
Commercial and Industrial | Energy Sector
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]	20,713	14,822
Unpaid Principal Balance, With no related allowance for credit losses		33,908	23,307
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses		20,713	14,822
Undisbursed Commitments, With no related allowance for credit losses		3,658	387
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]		39,857
Unpaid Principal Balance, With allowance for credit losses recorded			43,416
Related Specific Allowance, With allowance for credit losses recorded			8,353
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded			28,000
Undisbursed Commitments, With allowance for credit losses recorded			402
Commercial and Industrial | General C&I
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]		5,010
Unpaid Principal Balance, With no related allowance for credit losses			4,994
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses			192
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	28,684
Unpaid Principal Balance, With allowance for credit losses recorded		28,677
Related Specific Allowance, With allowance for credit losses recorded		3,559
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		24,103
Undisbursed Commitments, With allowance for credit losses recorded		930
Commercial and Industrial | Healthcare
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	4,496
Unpaid Principal Balance, With allowance for credit losses recorded		4,496
Related Specific Allowance, With allowance for credit losses recorded		256
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		4,496
Commercial and Industrial | Restaurant Industry
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	23,043	11,017
Unpaid Principal Balance, With allowance for credit losses recorded		23,698	10,969
Related Specific Allowance, With allowance for credit losses recorded		3,485	106
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		22,042
Undisbursed Commitments, With allowance for credit losses recorded		2,329	2,500
Consumer
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]	1,538	1,509
Unpaid Principal Balance, With no related allowance for credit losses		1,535	1,512
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses			35
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	254
Unpaid Principal Balance, With allowance for credit losses recorded		254
Related Specific Allowance, With allowance for credit losses recorded		25
Consumer | Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]	1,538	1,093
Unpaid Principal Balance, With no related allowance for credit losses		1,535	1,097
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses			35
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]		496
Unpaid Principal Balance, With allowance for credit losses recorded			494
Related Specific Allowance, With allowance for credit losses recorded			36
Consumer | Other
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]		416
Unpaid Principal Balance, With no related allowance for credit losses			415
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	254
Unpaid Principal Balance, With allowance for credit losses recorded		254
Related Specific Allowance, With allowance for credit losses recorded		25
Small Business Lending
Accounts Notes And Loans Receivable [Line Items]
Recorded Investment in Impaired Loans, With no related allowance for credit losses	[1]		249
Unpaid Principal Balance, With no related allowance for credit losses			695
Nonaccrual Loans Included in Impaired Loans, with no related allowance for credit losses			249
Recorded Investment in Impaired Loans, With allowance for credit losses recorded	[1]	476	650
Unpaid Principal Balance, With allowance for credit losses recorded		1,249	921
Related Specific Allowance, With allowance for credit losses recorded		107	27
Nonaccrual Loans Included in Impaired Loans, With allowance for credit losses recorded		229	$ 60
Undisbursed Commitments, With allowance for credit losses recorded		$ 10

[1] The recorded investment of a loan also includes any interest receivable, net unearned discount or fees, and unamortized premium or discount.