Debt (Parenthetical) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
In-substance defeased debt, interest payable monthly at 5.62% at September 30, 2013 and December 31, 2012, secured and paid by pledged treasury securities, due October 1, 2015
Debt Instrument [Line Items]
Debt interest rate	5.62%	5.62%
Debt instrument, maturity date	Oct. 01, 2015	Oct. 01, 2015
Community Development District debt, secured by certain real estate and standby note purchase agreements, due May 1, 2016 — May 1, 2039, bearing interest at 6.70% to 7.15% at September 30, 2013 and December 31, 2012
Debt Instrument [Line Items]
Debt instrument, minimum interest	6.70%	6.70%
Debt instrument, maximum interest	7.15%	7.15%
Debt instrument, maturity start date	May 01, 2016
Debt instrument, maturity end date	May 01, 2039