Commitments and Contingencies - Maturities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Leases with purchase options, annualized base rent receivables in next five years and thereafter
Leases with purchase option, annualized base rent receivables in 2016	$ 32,062
Leases with purchase option, annualized base rent receivables in 2017	15,078
Leases with purchase option, annualized base rent receivables in 2018	19,352
Leases with purchase option, annualized base rent receivables in 2019	25,863
Leases with purcase option, annualized base rent receivables in 2020	13,647
Leases with purchase option, annualized base rent receivables thereafter	54,009
Total leases with purchase option, annualized base rent receivables	$ 160,011
Number of properties with purchase options, annualized base rent receivables
Number of properties with a purchase option, annualized base rent receivables in 2016 | item	12
Number of properties with a purchase option, annualized base rent receivables in 2017 | item	10
Number of properties with a purchase option, annualized base rent receivables in 2018 | item	4
Number of properties with a purchase option, annualized base rent receivables in 2019 | item	14
Number of properties with a purchase option, annualized base rent receivables in 2020 | item	4
Number of properties with a purchase option, annualized base rent receivables thereafter | item	32
Total number of properties with a purchase option, annualized base rent receivables | item	76
Rental Expense
Rental expense attributable to continuing operations	$ 10,000	$ 8,000	$ 8,000
Maximum remaining term of ground leases excluding extension options	99 years
Future minimum lease obligations under non-cancelable ground and other operating leases
Future minimum lease obligations under non-cancelable ground and other operating leases, 2016	$ 7,870
Future minimum lease obligations under non-cancelable ground and other operating leases, 2017	7,160
Future minimum lease obligations under non-cancelable ground and other operating leases, 2018	6,908
Future minimum lease obligations under non-cancelable ground and other operating leases, 2019	7,063
Future minimum lease obligations under non-cancelable ground and other operating leases, 2020	6,656
Future minimum lease obligations under non-cancelable ground and other operating leases, Thereafter	348,249
Future minimum lease obligations under non-cancelable ground and other operating leases, Total	$ 383,906