Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended	9 Months Ended
	Aug. 18, 2015 shares	Dec. 10, 2014 USD ($) shares	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Oct. 17, 2014 USD ($) $ / shares
Property, Plant and Equipment [Line Items]
Accumulated amortization of deferred financing costs			$ 2,800,000	$ 2,800,000		$ 2,200,000
Reserve against receivables			0	$ 0		0
REIT taxable income to its stockholders, percentage - at least 90%				90.00%
REIT non qualifying period				4 years
Dividend declared			7,704,000	$ 7,704,000		$ 3,946,000
Dividend, payable date				Apr. 15, 2015
Dividend, record date				Mar. 31, 2015
Issuance of common stock, net, shares | shares	16,330,000
Stock-based compensation expense			435,000	$ 1,095,000	$ 0
Number of reportable segments | segment				1
Special Dividend [Member]
Property, Plant and Equipment [Line Items]
Dividend, declared date				Oct. 17, 2014
Dividend declared							$ 132,000,000
Dividend payable per share | $ / shares							$ 5.88
Dividend, payable date				Dec. 10, 2014
Dividend, record date				Oct. 31, 2014
Cash portion of dividend		$ 33,000,000
Stock portion of dividend		$ 99,000,000
Issuance of common stock, net, shares | shares		8,974,249
Interest Rate Swap [Member]
Property, Plant and Equipment [Line Items]
Interest rate swap outstanding			$ 0	$ 0