Basis of Presentation - Schedule of Impact of ASU 2016-13 (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2020		Dec. 31, 2019		Dec. 31, 2018	Mar. 31, 2020	Jan. 01, 2020	Jun. 30, 2019	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	$ 7,548,558	[1]	$ 7,137,152
Allowance for credit losses on loans	(114,609)		(62,224)		$ (60,996)	$ (96,850)	$ (62,224)	$ (61,479)	$ (61,409)
Total loans							7,074,928
Net deferred tax asset							13,206
Allowance for credit losses on unfunded loan commitments	7,004		3,112			6,077	3,113
Retained earnings	$ 692,240		$ 761,083				761,083
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member		us-gaap:AccountingStandardsUpdate201613Member		us-gaap:AccountingStandardsUpdate201602Member
As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans							(89,577)
Total loans							7,047,575
Net deferred tax asset							19,317
Allowance for credit losses on unfunded loan commitments			$ 4,461				4,462
Retained earnings							738,493
Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans			(27,352)				(27,353)
Total loans							(27,353)
Net deferred tax asset							6,111
Allowance for credit losses on unfunded loan commitments			1,349				1,349
Retained earnings							(22,590)
Commercial real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans					$ (33,707)			(32,836)	(34,903)
Commercial and industrial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans					(11,596)			(13,227)	(11,996)
Commercial and industrial | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans							(9,900)
Commercial construction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans					(7,983)			(7,254)	(6,757)
Consumer real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans					(6,187)			(6,571)	(6,178)
Other consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses on loans					$ (1,523)			$ (1,591)	$ (1,575)
Commercial | Commercial real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	$ 2,862,103	[1]	3,059,592				3,416,518
Allowance for credit losses on loans	(57,730)		(30,577)			(42,611)
Commercial | Commercial real estate | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							2,946,319
Commercial | Commercial real estate | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							(470,199)
Allowance for credit losses on loans			(4,810)
Commercial | Commercial and industrial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	1,682,676	[1]	1,480,529				1,720,833
Allowance for credit losses on loans	(19,164)		(15,681)			(19,870)
Commercial | Commercial and industrial | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							1,458,541
Commercial | Commercial and industrial | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							(262,292)
Allowance for credit losses on loans			(7,853)
Commercial | Commercial construction
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	453,098	[1]	370,060				375,445
Allowance for credit losses on loans	(8,874)		(7,900)			(6,606)
Commercial | Commercial construction | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							345,263
Commercial | Commercial construction | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							(30,182)
Allowance for credit losses on loans			3,376
Commercial | Business banking
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	1,268,835	[1]	846,790				0
Allowance for credit losses on loans	(14,404)	[2]	0	[2]		(13,706)
Commercial | Business banking | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							1,092,908
Commercial | Business banking | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							1,092,908
Allowance for credit losses on loans			(12,898)
Consumer | Consumer real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	1,202,113	[1]	1,295,207				1,545,323
Allowance for credit losses on loans	(11,585)		(6,337)			(11,200)
Consumer | Consumer real estate | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							1,235,352
Consumer | Consumer real estate | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							(309,971)
Allowance for credit losses on loans			(4,525)
Consumer | Other consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance	79,733	[1]	84,974				79,033
Allowance for credit losses on loans	$ (2,852)		(1,729)			$ (2,857)
Consumer | Other consumer | As Reported Under ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							58,769
Consumer | Other consumer | Impact of ASU 2016-13 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans held for investment, outstanding balance							$ (20,264)
Allowance for credit losses on loans			$ (642)

[1] We had 2,360 loans that were modified totaling $1.4 billion under the CARES Act at June 30, 2020. These customers were not considered past due as a result of their delayed payments. Upon exiting the loan modification deferral program, the measurement of loan delinquency will resume where it left off upon entry into the program. Due to the modification program, this delinquency table may not accurately reflect the credit risk associated with these loans.

[2] In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Our new segmentation breaks out business banking loans from our other loan segments: CRE, C&I, commercial construction, consumer real estate and other consumer. The business banking allowance balance at the beginning of period is included in the other segments and reclassified to business banking through the impact of CECL adoption line.