Senior Notes Payable - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended				0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Aug. 31, 2012	Jun. 30, 2014 Securities Repurchase Plan [Member]	Jun. 30, 2014 Securities Repurchase Plan [Member]
Debt Instrument [Line Items]
Senior notes payable	$ 75,072,000		$ 75,072,000		$ 86,250,000	$ 86,250,000
Senior notes issued percentage						7.75%
Senior notes issue price						100.00%
Maturity period of the assumed debt			Aug. 15, 2022
Notes interest rate	7.75%		7.75%
Redemption price of notes			100.00%
Outstanding Notes acquired	1,661,000		1,661,000		1,742,000			11,178,000
Aggregate price of outstanding Notes							11,742,000
Loss on extinguishment of debt	$ (564,000)	$ 0	$ (564,000)	$ 0			$ 564,000