Loans and Allowance - Changes in Allowance for Loan Losses by Loan Segment (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2021		Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 201,082		$ 99,454	$ 130,648	[1]	$ 80,284
Provision for credit losses - loans	0		21,895	0		41,647
Recoveries on loans	412		317	1,106		990
Loans charged off	(1,719)		(547)	(6,034)		(1,802)
Ending balance	199,775	[1]	121,119	199,775	[1]	121,119
Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				74,055
Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				204,703
Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				130,648
Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	65,722		38,431	47,115		32,902
Provision for credit losses - loans	(1,898)		6,240	(2,830)		11,941
Recoveries on loans	152		106	340		549
Loans charged off	(295)		(99)	(968)		(714)
Ending balance	63,681		44,678	63,681		44,678
Commercial | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				20,024
Commercial | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				67,139
Commercial | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				47,115
Commercial | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	70,861		37,907	40,786		28,778
Provision for credit losses - loans	2,842		8,945	1,141		18,139
Recoveries on loans	33		107	197		225
Loans charged off	(1,035)		(41)	(4,348)		(224)
Ending balance	72,701		46,918	72,701		46,918
Commercial Real Estate | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				34,925
Commercial Real Estate | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				75,711
Commercial Real Estate | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				51,070
Commercial Real Estate | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				(10,284)
Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	20,182			10,284
Provision for credit losses - loans	(3,106)			(2,011)
Recoveries on loans	1			1
Loans charged off	0			(2)
Ending balance	17,077			17,077
Construction | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				8,805
Construction | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				19,089
Construction | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Construction | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				10,284
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			5,752	0		4,035
Provision for credit losses - loans			2,783	0		4,707
Recoveries on loans			56	0		98
Loans charged off			(146)	0		(395)
Ending balance	0		8,445	0		8,445
Consumer | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Consumer | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Consumer | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				9,648
Consumer | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				(9,648)
Residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			17,364	0		14,569
Provision for credit losses - loans			3,927	0		6,860
Recoveries on loans			48	0		118
Loans charged off			(261)	0		(469)
Ending balance	0		$ 21,078	0		$ 21,078
Residential | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Residential | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Residential | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				22,815
Residential | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				(22,815)
Consumer & Residential
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	44,317			32,463
Provision for credit losses - loans	2,162			3,700
Recoveries on loans	226			568
Loans charged off	(389)			(716)
Ending balance	$ 46,316			46,316
Consumer & Residential | Impact of adopting ASC 326
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				10,301
Consumer & Residential | Adjusted balance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				42,764
Consumer & Residential | Previously reported
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				0
Consumer & Residential | Credit risk reclassifications
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				$ 32,463

[1] Beginning January 1, 2021, the amount is based on the current expected credit loss methodology. Prior to January 1, 2021, the amount is based on the incurred loss methodology. See additional details in NOTE 1. GENERAL of these Notes to Consolidated Condensed Financial Statement.