Debt Securities Held-to-maturity - Weighted average yield and contractual maturities of debt securities HTM (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Amortized cost
Amortized cost - Within 1 year	$ 503,564
Amortized cost - After 1 to 5 year	6,166,692
Amortized cost - After 5 to 10 years	2,639,263
Amortized cost - After 10 years	47,220
Amortized cost	9,356,739	$ 79,461
Book Value
Book Value - within 1 year	503,564
Book Value - Within 1 to 5 years	5,659,891
Book Balue - After 5 to 10 years	2,314,691
Book Value - After 10 years	47,220
Book Value	8,525,366	79,461
Allowance for credit losses
Allowance for credit losses	6,911	8,096
Net of Allowance
Net of Allowance	8,518,455	71,365
Gross unrecognized gains
Gross Unrealized Gains	4,918	12,003
Gross unrealized losses
Gross Unrealized Losses	83,177	0
Fair Value
Fair Value - within 1 year	497,358
Fair Value - After 1 to 5 years	5,599,919
Fair Value - After 5 to 10 years	2,299,834
Fair Value - After 10 years	43,085
Fair value	$ 8,440,196	$ 83,368
Weighted Average Yield
Weighted Average Yield	1.55%	3.06%
US Treasury Securities
Amortized cost
Amortized cost - Within 1 year	$ 499,034
Amortized cost - After 1 to 5 year	6,147,568
Amortized cost - After 5 to 10 years	2,638,238
Amortized cost	9,284,840
Book Value
Book Value - within 1 year	499,034
Book Value - Within 1 to 5 years	5,640,767
Book Balue - After 5 to 10 years	2,313,666
Book Value	8,453,467
Allowance for credit losses
Allowance for credit losses - Within 1 Year	0
Allowance for credit losses - After 1 to 5 years	0
Allowance for credit losses - After 5 to 10 years	0
Allowance for credit losses	0
Net of Allowance
Net of Allowance - Within 1 Year	499,034
Net of Allowance - After 1 to 5 Years	5,640,767
Net of Allowance - After 5 to 10 Years	2,313,666
Net of Allowance	8,453,467
Gross unrecognized gains
Gross unrealized gains - Within 1 year	0
Gross unrealized gains - After 1 to 5 years	0
Gross unrealized gains - After 5 to 10 years	0
Gross Unrealized Gains	0
Gross unrealized losses
Gross unrealized losses - Within 1 year	6,203
Gross unrealized losses - After 1 to 5 years	59,806
Gross unrealized losses - After 5 to 10 years	14,857
Gross Unrealized Losses	80,866
Fair Value
Fair Value - within 1 year	492,831
Fair Value - After 1 to 5 years	5,580,961
Fair Value - After 5 to 10 years	2,298,809
Fair value	$ 8,372,601
Weighted Average Yield
Weighted average yield - Within 1 Year	2.83%
Weighted average yield - After 1 to 5 years	1.49%
Weighted average yield - After 5 to 10 years	1.41%
Weighted Average Yield	1.54%
Obligations of Puerto Rico, States and political subdivisions
Amortized cost
Amortized cost - Within 1 year	$ 4,530	$ 4,240
Amortized cost - After 1 to 5 year	19,105	14,395
Amortized cost - After 5 to 10 years	1,025	11,280
Amortized cost - After 10 years	41,261	43,561
Amortized cost	65,921	73,476
Book Value
Book Value - within 1 year	4,530
Book Value - Within 1 to 5 years	19,105
Book Balue - After 5 to 10 years	1,025
Book Value - After 10 years	41,261
Book Value	65,921
Allowance for credit losses
Allowance for credit losses - Within 1 Year	8	7
Allowance for credit losses - After 1 to 5 years	234	148
Allowance for credit losses - After 5 to 10 years	34	122
Allowance for credit losses - After 10 years	6,635	7,819
Allowance for credit losses	6,911	8,096	$ 10,261
Net of Allowance
Net of Allowance - Within 1 Year	4,522	4,233
Net of Allowance - After 1 to 5 Years	18,871	14,247
Net of Allowance - After 5 to 10 Years	991	11,158
Net of Allowance - After 10 Years	34,626	35,742
Net of Allowance	59,010	65,380
Gross unrecognized gains
Gross unrealized gains - Within 1 year	5	4
Gross unrealized gains - After 1 to 5 years	150	149
Gross unrealized gains - After 5 to 10 years	34	104
Gross unrealized gains - After 10 years	4,729	11,746
Gross Unrealized Gains	4,918	12,003
Gross unrealized losses
Gross unrealized losses - Within 1 year	0	0
Gross unrealized losses - After 1 to 5 years	82	0
Gross unrealized losses - After 5 to 10 years	0	0
Gross unrealized losses - After 10 years	2,229	0
Gross Unrealized Losses	2,311	0
Fair Value
Fair Value - within 1 year	4,527	4,237
Fair Value - After 1 to 5 years	18,939	14,396
Fair Value - After 5 to 10 years	1,025	11,262
Fair Value - After 10 years	37,126	47,488
Fair value	$ 61,617	$ 77,383
Weighted Average Yield
Weighted average yield - Within 1 Year	6.08%	6.07%
Weighted average yield - After 1 to 5 years	4.24%	6.23%
Weighted average yield - After 5 to 10 years	5.80%	2.18%
Weighted average yield - After 10 years	1.40%	1.50%
Weighted Average Yield	2.61%	2.79%
Collateralized Mortgage Obligations - Federal agencies
Amortized cost
Amortized cost - After 1 to 5 year	$ 19	$ 25
Amortized cost	19	25
Book Value
Book Value - Within 1 to 5 years	19
Book Value	19
Allowance for credit losses
Allowance for credit losses - After 1 to 5 years	0	0
Allowance for credit losses	0	0
Net of Allowance
Net of Allowance - After 1 to 5 Years	19	25
Net of Allowance	19	25
Gross unrecognized gains
Gross unrealized gains - After 1 to 5 years	0	0
Gross Unrealized Gains	0	0
Gross unrealized losses
Gross unrealized losses - After 1 to 5 years	0	0
Gross Unrealized Losses	0	0
Fair Value
Fair Value - After 1 to 5 years	19	25
Fair value	$ 19	$ 25
Weighted Average Yield
Weighted average yield - After 1 to 5 years	6.44%	6.44%
Weighted Average Yield	6.44%	6.44%
Securities in wholly owned statutory business trusts
Amortized cost
Amortized cost - After 10 years	$ 5,959	$ 5,960
Amortized cost	5,959	5,960
Book Value
Book Value - After 10 years	5,959
Book Value	5,959
Allowance for credit losses
Allowance for credit losses - After 10 years	0	0
Allowance for credit losses	0	0
Net of Allowance
Net of Allowance - After 10 Years	5,959	5,960
Net of Allowance	5,959	5,960
Gross unrecognized gains
Gross unrealized gains - After 10 years	0	0
Gross Unrealized Gains	0	0
Gross unrealized losses
Gross unrealized losses - After 10 years	0	0
Gross Unrealized Losses	0	0
Fair Value
Fair Value - After 10 years	5,959	5,960
Fair value	$ 5,959	$ 5,960
Weighted Average Yield
Weighted average yield - After 10 years	6.33%	6.33%
Weighted Average Yield	6.33%	6.33%