Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2016 item
Revenue Recognition
Maximum period over which loan is to be considered as non-performing	60 days
Methods used for calculation of annual increases over the rents of the prior year	4
Maximum period over which a lease is to be considered as non-performing	60 days
Minimum
Revenue Recognition
Specified annual increase over the prior year's rent (as a percent)	2.00%
Maximum
Revenue Recognition
Specified annual increase over the prior year's rent (as a percent)	3.00%