Equity (Details) - USD ($)	1 Months Ended	6 Months Ended
	Jan. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, shares authorized (shares)		150,000,000	100,000,000	100,000,000
Cantor Fitzgerald & Co.
Class of Stock [Line Items]
Stock issued during the period (shares)		0
Cantor Fitzgerald & Co. | Common Stock
Class of Stock [Line Items]
Aggregate offering price	$ 50,000,000.0
Cantor Fitzgerald & Co.
Class of Stock [Line Items]
Fixed commission (percent)	3.00%