Segment Reporting - Adjusted Pretax Operating Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net gains (losses) on investments and other financial instruments	$ (16,252)	$ 2,098	$ (87,578)	$ 12,578
Amortization of other acquired intangible assets	(1,023)	(862)	(2,721)	(2,587)
Pretax income	255,461	161,641	749,481	518,326
Corporate, Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	2,581	986	6,397	2,920
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	(16,252)	2,098	(87,578)	12,578
Amortization of other acquired intangible assets	(1,023)	(862)	(2,721)	(2,587)
Impairment of other long-lived assets and other non-operating items	16	(244)	79	(4,349)
Mortgage
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	295,675	165,220	890,036	534,972
Allocated corporate operating expenses	32,457	33,963	101,903	94,177
Direct depreciation expense	2,234	2,240	6,803	7,342
Mortgage | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocated corporate operating expenses	700	800	2,300	2,500
homegenius
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	(25,536)	(5,557)	(56,732)	(25,208)
Allocated corporate operating expenses	5,555	4,918	16,554	13,635
Direct depreciation expense	646	639	1,932	1,828
homegenius | Depreciation Expense
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Allocated corporate operating expenses	200	100	400	400
Mortgage and homegenius segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Adjusted pretax operating income (loss)	$ 270,139	$ 159,663	$ 833,304	$ 509,764