Note 4 - Segment Reporting - Adjusted Pretax Operating Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	$ 157,567	$ 142,290	$ 503,665	$ 255,074
Net gains (losses) on investments and other financial instruments	2,098	17,652	12,578	42,901
Amortization and impairment of other acquired intangible assets	(862)	(961)	(2,587)	(2,919)
Consolidated pretax income (loss)	161,641	161,205	518,326	300,274
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net gains (losses) on investments and other financial instruments	2,098	17,652	12,578	42,901
Amortization and impairment of other acquired intangible assets	(862)	(961)	(2,587)	(2,919)
Impairment of other long-lived assets and other-non-operating items	(244)	(466)	(4,349)	(788)
Mortgage segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	163,124	147,336	528,873	267,182
Allocated corporate operating expenses	34,341	29,127	95,225	83,700
Direct depreciation expense	2,240	2,895	7,342	9,719
Mortgage segment | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocated corporate operating expenses	800	800	2,500	1,700
homegenius segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	(5,557)	(5,046)	(25,208)	(12,108)
Allocated corporate operating expenses	4,918	3,248	13,635	9,438
Direct depreciation expense	639	679	1,828	2,113
homegenius segment | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocated corporate operating expenses	100	100	400	200
All Other activities segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	$ 3,082	$ 2,690	$ 9,019	$ 6,006