Summary of Significant Accounting Policies - Finite-lived Intangible Assets Amortization Expense (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
In-place lease, net of accumulated amortization of $20,131 and $1,325 at December 31, 2014 and 2013, respectively	$ 435,684	$ 44,202
Above-market lease, net of accumulated amortization of $1,086 and $113 at December 31, 2014 and 2013, respectively	26,329	2,259
Below-market ground lease, net of accumulated amortization of $32 at December 31, 2014	817	0
Total intangible lease assets, net	462,830	46,461
Below-market leases, net of accumulated accretion of $1,211 and $129 at December 31, 2014 and 2013, respectively	21,676	5,854
Total intangible lease liabilities, net	21,676	5,854
Accumulated amortization, in-place lease	20,131	1,325
Accumulated amortization,off-market lease	1,086	113
Accumulated amortization, below-market ground lease	32
Accumulated amortization, off-market lease	$ 1,211	$ 129