Investment Securities - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Stock purchased			$ 10,763,038		$ 729,814
Net realized gain loss on investments			163,000	$ 5,000	0
Investment securities unrealized gains (losses)			(1,100,000)	117,000
Other Comprehensive Income Unrealized Gain (Loss) on Available-for-Sale Investment Securities, tax			414,962	44,022	0
Common Stock and Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased			360,000,000
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased		$ 2,000,000
Net realized gain loss on investments		155,000
Investment sold		$ 1,900,000
Convertible Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased	$ 1,000,000
Investment sold	$ 843,844,000
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased					730,000
REIT market capitalization value					$ 1,500,000,000
Net realized gain loss on investments			131,000	$ 5,000
Common Stock [Member] | Common Stock and Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased			7,900,000
Net realized gain loss on investments			(123,000)
Investment sold			1,800,000
Common Stock [Member] | Common Stock and Debt Securities [Member] | Put Option [Member]
Schedule of Available-for-sale Securities [Line Items]
Stock purchased			$ 600,634,000