Allowance for Loan Losses - Summary of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					$ 60,996				$ 56,390	$ 60,996	$ 56,390
Charge-offs										(16,189)	(14,589)
Recoveries										2,544	4,200
Net (Charge-offs)										(13,645)	(10,389)
Provision for loan losses	$ 2,105	[1]	$ 4,913	$ 2,205	5,649	$ 2,716	$ 462	$ 9,345	2,472	14,873	14,995	$ 13,883
Balance at End of Year	62,224					60,996				62,224	60,996	56,390
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					33,707				27,235	33,707	27,235
Charge-offs										(3,664)	(372)
Recoveries										137	309
Net (Charge-offs)										(3,527)	(63)
Provision for loan losses										397	6,535
Balance at End of Year	30,577					33,707				30,577	33,707	27,235
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					11,596				8,966	11,596	8,966
Charge-offs										(8,928)	(8,574)
Recoveries										1,388	1,723
Net (Charge-offs)										(7,540)	(6,851)
Provision for loan losses										11,625	9,481
Balance at End of Year	15,681					11,596				15,681	11,596	8,966
Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					7,983				13,167	7,983	13,167
Charge-offs										(406)	(2,630)
Recoveries										5	1,135
Net (Charge-offs)										(401)	(1,495)
Provision for loan losses										318	(3,689)
Balance at End of Year	7,900					7,983				7,900	7,983	13,167
Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					6,187				5,479	6,187	5,479
Charge-offs										(1,353)	(1,319)
Recoveries										637	541
Net (Charge-offs)										(716)	(778)
Provision for loan losses										866	1,486
Balance at End of Year	6,337					6,187				6,337	6,187	5,479
Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year					$ 1,523				$ 1,543	1,523	1,543
Charge-offs										(1,838)	(1,694)
Recoveries										377	492
Net (Charge-offs)										(1,461)	(1,202)
Provision for loan losses										1,667	1,182
Balance at End of Year	$ 1,729					$ 1,523				$ 1,729	$ 1,523	$ 1,543

[1] The DNB Merger is included in our consolidated financial statements beginning on December 1, 2019.