Supplemental disclosure on the consolidated statments of cash flows - Non-cash activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flow Noncash Investing And Financing Activities Disclosure Abstract
Loans transferred to other real estate	$ 16,986	$ 8,628
Loans transferred to other property	14,232	12,072
Total loans transferred to foreclosed assets	31,218	20,700
Loans transfered to other assets	1,681	5,678
Financed sales of other real estate assets	4,619	3,643
Financed sales of other foreclosed assets	10,823	6,435
Total financed sales of other foreclosed and real estate assets	15,442	10,078
Transfers from loans held-in-portfolio to loans held-for-sale	10,723	0
Transfers from loans held-for-sale to loans held-in-portfolio	0	7,283
Loans securitized into investment securities	84,221	92,067
Trades receivables from brokers and counterparties	5,280	32,043
Trades payable to brokers and counterparties	5,279	7,220
Recognition of mortgage servicing rights on securitizations or asset transfers	1,634	12,084
Loans booked under the GNMA buy-back option	30,211	5,782
Capitalization of lease right of use asset	$ 4,536	$ 155,727