Summary of Significant Accounting Policies and Estimates - Variable Interest Entity Disclosure (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Assets    
Net investments in properties $ 2,704,862 $ 2,678,223
Net investments in direct financing leases 508,392 495,564
In-place lease and tenant relationship intangible assets, net 438,551 445,223
Other assets, net 228,413 246,027
Total assets 4,698,923 4,613,190
Liabilities    
Non-recourse debt, net 2,022,250 1,881,774
Accounts payable, accrued expenses and other liabilities 128,911 133,948
Deferred income taxes 32,655 24,929
Total liabilities 2,383,919 2,318,595
Variable Interest Entity, Primary Beneficiary    
Assets    
Net investments in properties 313,000 309,030
Net investments in direct financing leases 315,251 303,112
In-place lease and tenant relationship intangible assets, net 19,336 20,269
Other assets, net 65,557 66,654
Total assets 714,896 705,535
Liabilities    
Non-recourse debt, net 265,874 262,830
Accounts payable, accrued expenses and other liabilities 14,440 15,662
Deferred income taxes 15,687 10,675
Total liabilities $ 296,673 $ 289,889