Loans and Allowance - Changes in Allowance for Loan Losses by Loan Segment (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2021		Sep. 30, 2020	Sep. 30, 2021		Sep. 30, 2020
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 199,775		$ 121,119	$ 130,648	[1]	$ 80,284
Provision for credit losses - loans	0		12,544	0		54,191
Recoveries on loans	835		427	1,941		1,417
Loans charged off	(638)		(7,364)	(6,672)		(9,166)
Ending balance	199,972	[1]	126,726	199,972	[1]	126,726
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	63,681		44,678	47,115		32,902
Provision for credit losses - loans	3,496		7,299	666		19,240
Recoveries on loans	204		197	544		746
Loans charged off	(137)		(6,827)	(1,105)		(7,541)
Ending balance	67,244		45,347	67,244		45,347
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	72,701		46,918	40,786		28,778
Provision for credit losses - loans	(3,850)		2,990	(2,709)		21,129
Recoveries on loans	370		46	567		271
Loans charged off	(115)		0	(4,463)		(224)
Ending balance	69,106		49,954	69,106		49,954
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	17,077			10,284
Provision for credit losses - loans	567			(1,444)
Recoveries on loans	0			1
Loans charged off	(4)			(6)
Ending balance	17,640			17,640
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			8,445	0		4,035
Provision for credit losses - loans			971	0		5,678
Recoveries on loans			54	0		152
Loans charged off			(92)	0		(487)
Ending balance	0		9,378	0		9,378
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			21,078	0		14,569
Provision for credit losses - loans			1,284	0		8,144
Recoveries on loans			130	0		248
Loans charged off			(445)	0		(914)
Ending balance	0		$ 22,047	0		$ 22,047
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	46,316			32,463
Provision for credit losses - loans	(213)			3,487
Recoveries on loans	261			829
Loans charged off	(382)			(1,098)
Ending balance	$ 45,982			45,982
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.