Bank segment - Contractual maturities of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available-for-sale
Due in one year or less	$ 2,213
Due after one year through five years	126,822
Due after five years through ten years	14,630
Due after ten years	0
Total amortized cost	143,665
Mortgage-backed securities — issued or guaranteed by U.S. Government agencies or sponsored agencies	1,465,232
Amortized cost	1,608,897
Held-to-maturity
Due in one year or less	0
Due after one year through five years	19,966
Due after five years through ten years	39,940
Due after ten years	0
Total amortized cost	59,906
Mortgage-backed securities — issued or guaranteed by U.S. Government agencies or sponsored agencies	1,165,011
Held-to-maturity investment securities, at amortized cost	1,224,917	$ 1,251,747
Available-for-sale
Due in one year or less	2,177
Due after one year through five years	116,716
Due after five years through ten years	14,630
Due after ten years	0
Total fair value	133,523
Mortgage-backed securities — issued or guaranteed by U.S. Government agencies or sponsored agencies	1,234,514
Available-for-sale investment securities, at fair value	1,368,037	$ 1,429,667
Held-to-maturity
Due in one year or less	0
Due after one year through five years	17,403
Due after five years through ten years	34,296
Due after ten years	0
Total fair value	51,699
Mortgage-backed securities — issued or guaranteed by U.S. Government agencies or sponsored agencies	1,070,296
Held-to-maturity investment securities	$ 1,121,995