Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Housing Completed or Under Construction [Member]
Net changes in assets and liabilities:
Housing completed or under construction	$ (186,805,000)	$ (41,474,000)
Land and Land Under Development [Member]
Net changes in assets and liabilities:
Housing completed or under construction	122,701,000	36,919,000
Net income	36,476,000	28,418,000
Stock-based compensation expense	6,163,000	2,591,000
Depreciation and amortization	2,367,000	2,092,000
Inventory impairments	1,600,000	350,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	719,000	0
Gain on sale of marketable securities	(262,000)	(462,000)
Amortization of discount / premiums on marketable debt securities, net		100,000
Deferred income tax expense	7,873,000	16,267,000
Restricted cash	(196,000)	(2,128,000)
Trade and other receivables	(26,235,000)	(292,000)
Mortgage loans held-for-sale	(3,029,000)	8,664,000
Prepaid expenses and other assets	(2,975,000)	(3,118,000)
Accounts payable and accrued liabilities	19,517,000	(3,418,000)
Net cash provided by (used in) operating activities	(22,086,000)	44,509,000
Investing Activities:
Purchases of marketable securities	(15,426,000)	(34,679,000)
Maturities of marketable securities		1,510,000
Sales of marketable securities	50,765,000	50,179,000
Purchases of property and equipment	(3,117,000)	(421,000)
Net cash provided by investing activities	32,222,000	16,589,000
Financing Activities:
Advances (payments) on mortgage repurchase facility, net	4,686,000	(10,822,000)
Dividend payments	(24,504,000)	(24,425,000)
Proceeds from exercise of stock options		612,000
Net cash used in financing activities	(19,818,000)	(34,635,000)
Net increase (decrease) in cash and cash equivalents	(9,682,000)	26,463,000
Cash and cash equivalents:
Beginning of period	180,988,000	153,825,000
End of period	$ 171,306,000	$ 180,288,000