Allowance for Credit Losses and Credit Quality Information - Schedule of Allowance for Loan Losses and Loan Balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for credit losses
Beginning balance	$ 228,804	$ 47,576
Charge-offs	(28,315)	(13,521)
Recoveries	11,105	5,714
(Credit) provision	(117,087)	153,180	$ 25,560
Ending balance	94,507	228,804	47,576
Allowance for loan and lease losses
Beginning balance		47,576	39,539
Charge-offs			(22,273)
Recoveries			4,750
(Credit) provision			24,473
Provision for acquired loans			1,087
Ending balance			47,576
Loans evaluated on an individual basis	8	14	1,841
Loans evaluated on a collective basis	94,499	228,790	45,335
Acquired loans evaluated for impairment			400
Loans evaluated on an individual basis	21,138	49,224	36,589
Loans evaluated on a collective basis	7,860,917	8,965,453	5,179,722
Acquired nonimpaired loans			3,221,316
Acquired impaired loans			26,935
Ending balance	7,882,055	9,014,677	8,464,562
Reverse mortgage, fair value	3,900	10,100	16,600
Initial allowance on loans purchased with credit deterioration		100
Performing TDRs	14,204	15,539	14,300
Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		35,855
Ending balance			35,855
Commercial | Commercial and industrial
Allowance for credit losses
Beginning balance	150,875	22,849
Charge-offs	(23,592)	(10,388)
Recoveries	8,756	4,255
(Credit) provision	(86,072)	114,412
Ending balance	49,967	150,875	22,849
Allowance for loan and lease losses
Beginning balance		22,849	14,211
Charge-offs			(17,258)
Recoveries			1,621
(Credit) provision			23,977
Provision for acquired loans			298
Ending balance			22,849
Loans evaluated on an individual basis	1	1	1,179
Loans evaluated on a collective basis	49,966	150,874	21,664
Acquired loans evaluated for impairment			6
Loans evaluated on an individual basis	8,363	14,048	11,158
Loans evaluated on a collective basis	2,261,956	2,935,255	1,619,549
Acquired nonimpaired loans			603,157
Acquired impaired loans			1,564
Ending balance	2,270,319	2,949,303	2,235,428
Commercial | Commercial and industrial | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		19,747
Ending balance			19,747
Commercial | Owner-occupied commercial
Allowance for credit losses
Beginning balance	9,615	4,616
Charge-offs	(83)	(336)
Recoveries	160	142
(Credit) provision	(5,118)	6,665
Ending balance	4,574	9,615	4,616
Allowance for loan and lease losses
Beginning balance		4,616	5,057
Charge-offs			(354)
Recoveries			200
(Credit) provision			(472)
Provision for acquired loans			185
Ending balance			4,616
Loans evaluated on an individual basis	0	0	23
Loans evaluated on a collective basis	4,574	9,615	4,383
Acquired loans evaluated for impairment			210
Loans evaluated on an individual basis	1,690	6,496	4,060
Loans evaluated on a collective basis	1,340,017	1,326,231	971,694
Acquired nonimpaired loans			313,955
Acquired impaired loans			6,757
Ending balance	1,341,707	1,332,727	1,296,466
Commercial | Owner-occupied commercial | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		(1,472)
Ending balance			(1,472)
Commercial | Commercial mortgages
Allowance for credit losses
Beginning balance	31,071	7,452
Charge-offs	(73)	(104)
Recoveries	269	158
(Credit) provision	(19,644)	21,903
Ending balance	11,623	31,071	7,452
Allowance for loan and lease losses
Beginning balance		7,452	6,806
Charge-offs			(159)
Recoveries			1,546
(Credit) provision			(830)
Provision for acquired loans			89
Ending balance			7,452
Loans evaluated on an individual basis	7	13	0
Loans evaluated on a collective basis	11,616	31,058	7,387
Acquired loans evaluated for impairment			65
Loans evaluated on an individual basis	3,764	20,309	1,753
Loans evaluated on a collective basis	1,877,746	2,065,753	1,105,174
Acquired nonimpaired loans			1,107,379
Acquired impaired loans			8,670
Ending balance	1,881,510	2,086,062	2,222,976
Commercial | Commercial mortgages | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		1,662
Ending balance			1,662
Commercial | Construction
Allowance for credit losses
Beginning balance	12,190	3,891
Charge-offs	(2,473)	0
Recoveries	0	36
(Credit) provision	(7,814)	7,582
Ending balance	1,903	12,190	3,891
Allowance for loan and lease losses
Beginning balance		3,891	3,712
Charge-offs			(42)
Recoveries			4
(Credit) provision			207
Provision for acquired loans			10
Ending balance			3,891
Loans evaluated on an individual basis	0	0	0
Loans evaluated on a collective basis	1,903	12,190	3,867
Acquired loans evaluated for impairment			24
Loans evaluated on an individual basis	0	79	0
Loans evaluated on a collective basis	687,213	716,196	437,999
Acquired nonimpaired loans			142,592
Acquired impaired loans			491
Ending balance	687,213	716,275	581,082
Commercial | Construction | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		681
Ending balance			681
Residential
Allowance for credit losses
Beginning balance	6,893	1,381
Charge-offs	0	(229)
Recoveries	789	230
(Credit) provision	(4,330)	(2,011)
Ending balance	3,352	6,893	1,381
Allowance for loan and lease losses
Beginning balance		1,381	1,428
Charge-offs			(322)
Recoveries			(84)
(Credit) provision			126
Provision for acquired loans			233
Ending balance			1,381
Loans evaluated on an individual basis	0	0	463
Loans evaluated on a collective basis	3,352	6,893	824
Acquired loans evaluated for impairment			94
Loans evaluated on an individual basis	5,000	5,921	12,151
Loans evaluated on a collective basis	537,733	758,472	145,582
Acquired nonimpaired loans			834,820
Acquired impaired loans			7,326
Ending balance	542,733	764,393	999,879
Residential | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		7,522
Ending balance			7,522
Consumer
Allowance for credit losses
Beginning balance	18,160	7,387
Charge-offs	(2,094)	(2,464)
Recoveries	1,131	893
(Credit) provision	5,891	4,629
Ending balance	23,088	18,160	7,387
Allowance for loan and lease losses
Beginning balance		7,387	8,325
Charge-offs			(4,138)
Recoveries			1,463
(Credit) provision			1,465
Provision for acquired loans			272
Ending balance			7,387
Loans evaluated on an individual basis	0	0	176
Loans evaluated on a collective basis	23,088	18,160	7,210
Acquired loans evaluated for impairment			1
Loans evaluated on an individual basis	2,321	2,371	7,467
Loans evaluated on a collective basis	1,156,252	1,163,546	899,724
Acquired nonimpaired loans			219,413
Acquired impaired loans			2,127
Ending balance	$ 1,158,573	1,165,917	1,128,731
Consumer | Impact of adoption ASC 326
Allowance for credit losses
Beginning balance		$ 7,715
Ending balance			$ 7,715