Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities:
Net Income	$ 367,582	$ 238,312	$ 210,780
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Stock-based compensation expense	30,062	26,016	14,017
Depreciation and amortization	27,166	23,054	21,326
Inventory impairments	0	935	21,850
Net (gain) loss on marketable equity securities	8,285	(11,797)	3,745
Amortization of discount / premiums on marketable debt securities	0	0	(366)
Deferred income tax expense	10,688	13,670	3,729
Net changes in assets and liabilities:
Trade and other receivables	(12,815)	(12,997)	(4,638)
Mortgage loans held-for-sale	(35,535)	(47,810)	(11,097)
Prepaids and other assets	(44,932)	(4,694)	(245)
Accounts payable and accrued liabilities	91,318	66,205	49,325
Net cash provided by (used in) operating activities	(23,095)	57,833	(7,906)
Investing Activities:
Purchases of marketable securities	(10,804)	(11,708)	(18,850)
Maturities of marketable securities	0	0	50,000
Sales of marketable securities	59,266	7,637	16,230
Purchases of property and equipment	(26,777)	(24,714)	(27,166)
Net cash provided by (used in) investing activities	21,685	(28,785)	20,214
Financing Activities:
Advances on mortgage repurchase facility, net	52,774	32,801	4,475
Payments of senior notes	(250,000)	0	0
Proceeds from issuance of senior notes	298,050	0	0
Dividend payments	(89,008)	(73,117)	(67,718)
Payments of deferred debt issuance costs	(4,471)	0	(3,026)
Issuance of shares under stock-based compensation programs, net	28,825	15,341	9,860
Net cash provided by (used in) financing activities	31,170	(24,975)	(56,409)
Net increase (decrease) in cash, cash equivalents and restricted cash	29,760	4,073	(44,101)
Cash, cash equivalents and restricted cash:
Beginning of year	474,212	470,139	514,240
End of year	503,972	474,212	470,139
Reconciliation of cash, cash equivalents and restricted cash:
Total cash, cash equivalents and restricted cash	474,212	474,212	470,139
Homebuilding Line of Credit Facility [Member]
Financing Activities:
Payments on homebuilding line of credit, net	(5,000)	0	0
Homebuilding Segment
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Inventory impairments	0	935	21,850
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	411,362	424,186	414,724
Restricted cash	15,343	14,279	6,363
Financial Services Segment
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	77,267	35,747	49,052
Housing completed or under construction
Net changes in assets and liabilities:
Housing completed or under construction and land under development	(449,882)	(83,484)	(12,082)
Land and land under development
Net changes in assets and liabilities:
Housing completed or under construction and land under development	$ (15,032)	$ (149,577)	$ (304,250)