Summary of Significant Accounting Policies - Additional Information (Detail)		3 Months Ended	6 Months Ended
	Dec. 10, 2014 USD ($) shares	Jun. 30, 2015 USD ($)	Jun. 30, 2015 USD ($) Segment	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Oct. 17, 2014 USD ($) $ / shares
Property, Plant and Equipment [Line Items]
Accumulated amortization of deferred financing costs		$ 3,300,000	$ 3,300,000		$ 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		5,090,000	$ 5,090,000		$ 3,946,000
Dividend, record date			Mar. 31, 2015
Dividend, payable date			Apr. 15, 2015
Stock-based compensation expense		294,000	$ 660,000	$ 0
Number of reportable segments | Segment			1
Special Dividend [Member]
Property, Plant and Equipment [Line Items]
Dividend declared						$ 132,000,000
Cash portion of dividend	$ 33,000,000
Stock portion of dividend	$ 99,000,000
Common stock shares issued | shares	8,974,249
Dividend payable per share | $ / shares						$ 5.88
Dividend, declared date			Oct. 17, 2014
Dividend, record date			Oct. 31, 2014
Dividend, payable date			Dec. 10, 2014
Interest Rate Swap [Member]
Property, Plant and Equipment [Line Items]
Interest rate swap outstanding		$ 0	$ 0