Notes Payable (Details) (USD $)	0 Months Ended	12 Months Ended			1 Months Ended	9 Months Ended
	Apr. 07, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2012	Sep. 30, 2014	Dec. 31, 2011	Jan. 31, 2011	Feb. 15, 2014	Feb. 04, 2011	Aug. 31, 2014
Debt Instrument [Line Items]
Line Of Credit Facility, Maximum Borrowing Capacity, Limitation, Percent	100.00%
Line of Credit Facility, Maximum Borrowing Capacity, Percentage of Appraised Value Restriction	85.00%
Long-term Debt		$ 299,956,000	$ 105,402,000
Financial covenants: [Abstract]
Minimum cash and cash equivalents		180,334,000	144,727,000	79,815,000			124,316,000
Repurchase Right [Abstract]
Percentage of face value the notes were sold to the public								100.00%
Interest payments		7,600,000	7,900,000	7,600,000
Maturities of notes payable:
2015		0
2016		99,956,000
2017		0
2018		0
2019		200,000,000
Thereafter		0
Total Corporate		299,956,000
Line of Credit Facility, Maximum Borrowing Capacity, Percentage of Appraised Value Restriction of Lots Under Development	65.00%
Line of Credit Facility, Maximum Borrowing Capacity, Percentage of Appraised Value Restriction Land	50.00%
Commitment fee (percent)		0.50%
Line of Credit [Member]
Debt Instrument [Line Items]
Line Of Credit Facility, Maximum Borrowing Capacity, Swing Line	30,000,000
Line of Credit Facility, Amount Outstanding						0
Maturities of notes payable:
Line of Credit Facility, Maximum Borrowing Capacity		82,400,000
Line Of Credit Facility, Conditional Maximum Borrowing Capacity	175,000,000	0
Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		3.25%
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Maturities of notes payable:
Basis spread on variable rate		3.25%
Revolving Credit Facility [Member] | Prime Rate [Member]
Maturities of notes payable:
Basis spread on variable rate		2.25%
4.50% Notes [Member]
Debt Instrument [Line Items]
Outstanding debt			5,402,000
7.50% Notes [Member]
Debt Instrument [Line Items]
Outstanding debt		55,481,000	55,500,000
Face amount of debt instrument										100,000,000
Stated interest rate (percent)					7.50%					7.50%
Write off of deferred costs					1,100,000
Repurchase amount of debt instrument									19,000
Redemption price percentage (percent)		100.00%
Financial covenants: [Abstract]
Convertible, number of equity instruments (in shares)		33.3333
Principal conversion standard base unit (in dollars per share)		$ 1
Convertible conversion price (in dollars per share)		$ 30.00
Redemption right [Abstract]
Number of trading days the entity may redeem outstanding Notes		20
Number of consecutive trading days		30 days
Convertible conversion price percentage (in hundredths)		130.00%
Principal amount of debt retired					44,500,000
7.50% Senior Exchange Convertible Notes Member [Member]
Debt Instrument [Line Items]
Outstanding debt		44,500,000
Face amount of debt instrument		44,500,000	44,500,000
Stated interest rate (percent)					7.50%
Financial covenants: [Abstract]
Convertible, number of equity instruments (in shares)		55.5555
Principal conversion standard base unit (in dollars per share)		$ 1,000
Convertible conversion price (in dollars per share)		$ 18.00
Redemption right [Abstract]
Convertible conversion price percentage (in hundredths)		130.00%
7.5% Senior Exchange Convertible Notes [Member]
Debt Instrument [Line Items]
Outstanding debt		44,475,000	44,500,000
Eight Point Five Percent Senior Notes Due Twenty Nineteen [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Outstanding debt		200,000,000
Face amount of debt instrument						200,000,000
Stated interest rate (percent)						8.50%
Eight Point Five Percent Senior Notes Due Twenty Nineteen [Member] | Senior Notes [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed						35.00%
Redemption price percentage (percent)						108.50%
Eight Point Five Percent Senior Notes Due Twenty Nineteen [Member] | Senior Notes [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Redemption price percentage (percent)		106.375%
Eight Point Five Percent Senior Notes Due Twenty Nineteen [Member] | Senior Notes [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument [Line Items]
Redemption price percentage (percent)		103.188%
Eight Point Five Percent Senior Notes Due Twenty Nineteen [Member] | Senior Notes [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument [Line Items]
Redemption price percentage (percent)		100.00%
JPMorgan Chase Bank, N.A. [Member] | Line of Credit [Member]
Maturities of notes payable:
Line of Credit Facility, Maximum Borrowing Capacity	65,000,000
Ratio of Indebtedness to Net Capital		0.6
Tangible net worth (at least)		228,900,000.0
Cumulative consolidated net income (at least)		50.00%
Proceeds of equity offerings, net (at least)		50.00%
JPMorgan Chase Bank, N.A. [Member] | Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		0.125%
Citibank N.A. [Member] | Line of Credit [Member]
Maturities of notes payable:
Line of Credit Facility, Maximum Borrowing Capacity											25,000,000
Citibank N.A. [Member] | Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		0.125%
Royal Bank of Canada [Member] | Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		0.125%
DEUTSCHE BOERSE AG [Member] | Line of Credit [Member]
Maturities of notes payable:
Line of Credit Facility, Maximum Borrowing Capacity		$ 0
DEUTSCHE BOERSE AG [Member] | Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		0.125%
Credit Suisse AG [Member] | Revolving Credit Facility [Member]
Maturities of notes payable:
Unused capacity fee (percent)		0.125%