Senior Notes, Secured, and Subordinated Indebtedness - Schedule of Maturities of Notes Payable, Senior Unsecured Credit Facility, Subordinated Amortizing Notes and Senior Notes (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
2016		$ 15,378
2017		160,607
2018		13,262
2019		150,000
2020		425,000
Thereafter		350,000
Total Debt		1,114,247
Notes payable		175,181	$ 39,235
Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		225,800
Outstanding		110,200
November 2015 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		42,500
Outstanding		$ 15,000
Current Rate		4.50%
August 2015 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 14,200
Outstanding		$ 2,800
Current Rate		4.50%
August 2015 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 37,500
Outstanding		$ 13,200
Current Rate		4.50%
July 2015 Construction Notes Payable Due 2018 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 22,500
Outstanding		$ 13,300
Current Rate		4.00%
April 2015 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 18,500
Outstanding		$ 10,600
Current Rate		4.00%
November 2014 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 24,000
Outstanding		$ 19,100
Current Rate		4.00%
November 2014 Construction Notes Payable Due 2017 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable		$ 22,000
Outstanding		$ 20,800
Current Rate		4.00%
March 2014 Construction Notes Payable Due 2016 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable	[1]	$ 26,000
Outstanding		$ 15,000
Current Rate	[1]	3.42%
December 2013 Construction Notes Payable Due 2016 | Construction Notes Payable Agreement
Debt Instrument [Line Items]
Notes payable	[1]	$ 18,600
Outstanding		$ 400
Current Rate	[1]	4.50%

[1] Loan bears interest at the Company's option of either LIBOR +3.0% or the prime rate +1.0%.