Fair Value of Financial Assets and Liabilities - Fair Value Hierarchy of Financial Assets and Liabilities under U.S. GAAP Guidance (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets:
Marketable securities		$ 524,569
Loans held for sale, at fair value	$ 572,670	1,072,479
Debt securities		0
Total assets	603,602	1,605,549
Liabilities:
Contingent consideration	10,207	12,338
Total Liabilities	23,938	17,354
Rate lock commitments
Assets:
Derivative asset	9,049	3,957
Liabilities:
Derivative liability	13,364	2,836
Nasdaq Forwards
Assets:
Derivative asset		0
Forward sale contracts
Assets:
Derivative asset	21,883	4,544
Liabilities:
Derivative liability	367	2,180
Level 1
Assets:
Marketable securities		524,569
Loans held for sale, at fair value	0	0
Debt securities		0
Total assets	0	524,569
Liabilities:
Contingent consideration	0	0
Total Liabilities	0	0
Level 1 | Rate lock commitments
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Level 1 | Nasdaq Forwards
Assets:
Derivative asset		0
Level 1 | Forward sale contracts
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Level 2
Assets:
Marketable securities		0
Loans held for sale, at fair value	572,670	1,072,479
Debt securities		0
Total assets	572,670	1,072,479
Liabilities:
Contingent consideration	0	0
Total Liabilities	0	0
Level 2 | Rate lock commitments
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Level 2 | Nasdaq Forwards
Assets:
Derivative asset		0
Level 2 | Forward sale contracts
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Level 3
Assets:
Marketable securities		0
Loans held for sale, at fair value	0	0
Debt securities		0
Total assets	30,932	8,501
Liabilities:
Contingent consideration	10,207	12,338
Total Liabilities	23,938	17,354
Level 3 | Rate lock commitments
Assets:
Derivative asset	9,049	3,957
Liabilities:
Derivative liability	13,364	2,836
Level 3 | Nasdaq Forwards
Assets:
Derivative asset		0
Level 3 | Forward sale contracts
Assets:
Derivative asset	21,883	4,544
Liabilities:
Derivative liability	$ 367	$ 2,180