Allowance for Credit Losses - Disaggregated analysis of the changes in allowance for credit losses (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jun. 07, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Allowance for credit losses
Balance at beginning of period		$ 144,785	$ 56,522	$ 56,927	$ 55,798
Charge-offs		(2,431)	(2,862)	(5,654)	(4,481)
Recoveries		2,330	991	4,239	1,949
Net charge-offs		(101)	(1,871)	(1,415)	(2,532)
Provision (benefit)		29,536	3,704	64,270	5,192
Balance at end of period		434,608	58,213	434,608	58,213
Quantitative allowance
Collectively evaluated		356,187		356,187
Individually evaluated		10,904		10,904
Total quantitative allowance		367,091		367,091
Qualitative allowance		67,517		67,517
Provision for loan losses charged to operations		29,536	$ 3,704	64,270	$ 5,192
Unfunded Commitment
Allowance for credit losses
Provision (benefit)		12,500		14,300
Quantitative allowance
Provision for loan losses charged to operations		12,500		14,300
Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		150,946		3,408
Balance at end of period		150,946		150,946
Adjustments
Allowance for credit losses
Balance at beginning of period		405,173		111,365
Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		109,442		51,030
Balance at end of period		109,442		109,442
Mortgage
Allowance for credit losses
Balance at beginning of period		16,033		5,076
Charge-offs		(103)		(407)
Recoveries		187		406
Net charge-offs		84		(1)
Provision (benefit)		1,999		8,186
Balance at end of period		65,764		65,764
Quantitative allowance
Collectively evaluated		59,681		59,681
Individually evaluated		160		160
Total quantitative allowance		59,841		59,841
Qualitative allowance		5,923		5,923
Provision for loan losses charged to operations		1,999		8,186
Mortgage | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		30,710		98
Balance at end of period		30,710		30,710
Mortgage | Adjustments
Allowance for credit losses
Balance at beginning of period		63,681		9,931
Mortgage | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		16,938		4,757
Balance at end of period		16,938		16,938
HELOC
Allowance for credit losses
Balance at beginning of period		12,050		4,310
Charge-offs		(68)		(683)
Recoveries		203		608
Net charge-offs		135		(75)
Provision (benefit)		5,028		8,856
Balance at end of period		26,560		26,560
Quantitative allowance
Collectively evaluated		23,527		23,527
Individually evaluated		299		299
Total quantitative allowance		23,826		23,826
Qualitative allowance		2,734		2,734
Provision for loan losses charged to operations		5,028		8,856
HELOC | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		5,119		286
Balance at end of period		5,119		5,119
HELOC | Adjustments
Allowance for credit losses
Balance at beginning of period		21,397		8,432
HELOC | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		4,228		3,836
Balance at end of period		4,228		4,228
Non MOHO
Allowance for credit losses
Balance at beginning of period		2,732		1,142
Charge-offs		(249)		(479)
Recoveries		78		113
Net charge-offs		(171)		(366)
Provision (benefit)		2,018		2,710
Balance at end of period		9,545		9,545
Quantitative allowance
Collectively evaluated		6,213		6,213
Total quantitative allowance		6,213		6,213
Qualitative allowance		3,332		3,332
Provision for loan losses charged to operations		2,018		2,710
Non MOHO | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		1,130		14
Balance at end of period		1,130		1,130
Non MOHO | Adjustments
Allowance for credit losses
Balance at beginning of period		7,698		2,235
Non MOHO | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		3,836		1,079
Balance at end of period		3,836		3,836
Mobile Home
Allowance for credit losses
Balance at beginning of period		4,458		2,176
Charge-offs		(26)		(406)
Recoveries		64		117
Net charge-offs		38		(289)
Provision (benefit)		(1,110)		(582)
Balance at end of period		8,376		8,376
Quantitative allowance
Collectively evaluated		8,202		8,202
Total quantitative allowance		8,202		8,202
Qualitative allowance		174		174
Provision for loan losses charged to operations		(1,110)		(582)
Mobile Home | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		4,990		655
Balance at end of period		4,990		4,990
Mobile Home | Adjustments
Allowance for credit losses
Balance at beginning of period		9,448		4,257
Mobile Home | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period				1,426
Ready Reserves
Allowance for credit losses
Balance at beginning of period		513		231
Charge-offs		(106)		(205)
Recoveries				5
Net charge-offs		(106)		(200)
Provision (benefit)		95		251
Balance at end of period		502		502
Quantitative allowance
Collectively evaluated		460		460
Total quantitative allowance		460		460
Qualitative allowance		42		42
Provision for loan losses charged to operations		95		251
Ready Reserves | Adjustments
Allowance for credit losses
Balance at beginning of period		513		451
Ready Reserves | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period				220
Overdrafts
Allowance for credit losses
Balance at beginning of period		855		561
Charge-offs		(742)		(1,818)
Recoveries		288		662
Net charge-offs		(454)		(1,156)
Provision (benefit)		665		1,124
Balance at end of period		1,066		1,066
Quantitative allowance
Collectively evaluated		955		955
Total quantitative allowance		955		955
Qualitative allowance		111		111
Provision for loan losses charged to operations		665		1,124
Overdrafts | Adjustments
Allowance for credit losses
Balance at beginning of period		855		1,098
Overdrafts | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period				537
Land
Allowance for credit losses
Balance at beginning of period		7,254		3,055
Charge-offs		(100)		(205)
Recoveries		571		743
Net charge-offs		471		538
Provision (benefit)		2,527		3,737
Balance at end of period		30,155		30,155
Quantitative allowance
Collectively evaluated		32,961		32,961
Individually evaluated		63		63
Total quantitative allowance		33,024		33,024
Qualitative allowance		(2,869)		(2,869)
Provision for loan losses charged to operations		2,527		3,737
Land | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		7,338		348
Balance at end of period		7,338		7,338
Land | Adjustments
Allowance for credit losses
Balance at beginning of period		27,157		5,977
Land | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		12,565		2,574
Balance at end of period		12,565		12,565
CRE-OO and C&I
Allowance for credit losses
Balance at beginning of period		40,345		18,189
Charge-offs		(698)		(1,059)
Recoveries		710		955
Net charge-offs		12		(104)
Provision (benefit)		63		4,941
Balance at end of period		130,990		130,990
Quantitative allowance
Collectively evaluated		109,525		109,525
Individually evaluated		6,240		6,240
Total quantitative allowance		115,765		115,765
Qualitative allowance		15,225		15,225
Provision for loan losses charged to operations		63		4,941
CRE-OO and C&I | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		54,973		907
Balance at end of period		54,973		54,973
CRE-OO and C&I | Adjustments
Allowance for credit losses
Balance at beginning of period		130,915		35,583
CRE-OO and C&I | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		35,597		16,487
Balance at end of period		35,597		35,597
CRE and OIPP
Allowance for credit losses
Balance at beginning of period		57,437		20,800
Charge-offs		(23)		(23)
Recoveries		213		414
Net charge-offs		190		391
Provision (benefit)		15,942		32,490
Balance at end of period		156,533		156,533
Quantitative allowance
Collectively evaluated		111,087		111,087
Individually evaluated		3,916		3,916
Total quantitative allowance		115,003		115,003
Qualitative allowance		41,530		41,530
Provision for loan losses charged to operations		15,942		32,490
CRE and OIPP | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period		46,686		1,010
Balance at end of period		46,686		46,686
CRE and OIPP | Adjustments
Allowance for credit losses
Balance at beginning of period		140,401		40,688
CRE and OIPP | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period		36,278		18,878
Balance at end of period		36,278		36,278
BEX and Micro
Allowance for credit losses
Balance at beginning of period		2,665		1,148
Charge-offs		(316)		(369)
Recoveries		16		216
Net charge-offs		(300)		(153)
Provision (benefit)		2,071		2,344
Balance at end of period		4,436		4,436
Quantitative allowance
Collectively evaluated		3,576		3,576
Individually evaluated		226		226
Total quantitative allowance		3,802		3,802
Qualitative allowance		634		634
Provision for loan losses charged to operations		2,071		2,344
BEX and Micro | Initial PCD Allowance
Allowance for credit losses
Balance at beginning of period				90
BEX and Micro | Adjustments
Allowance for credit losses
Balance at beginning of period		2,665		2,245
BEX and Micro | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period				1,007
In transit
Allowance for credit losses
Balance at beginning of period		443		239
Provision (benefit)		238		213
Balance at end of period		681		681
Quantitative allowance
Qualitative allowance		681		681
Provision for loan losses charged to operations		238		213
In transit | Adjustments
Allowance for credit losses
Balance at beginning of period		443		468
In transit | Adjustments | ASU 2016-13
Allowance for credit losses
Balance at beginning of period				229
CSFL
Allowance for credit losses
Charge-offs	$ (158,200)
CSFL | Unfunded Commitment
Allowance for credit losses
Provision (benefit)		9,600		9,600
Quantitative allowance
Provision for loan losses charged to operations		$ 9,600		$ 9,600