Investments - Schedule of Lease Intangible Assets and Liabilities, Net of Accumulated Amortization (Details) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Capital Leased Assets [Line Items] | ||
| Less: accumulated amortization | $ (246,153) | $ (220,520) |
| Intangible lease assets, net | 484,600 | 526,718 |
| Less: accumulated amortization | (50,732) | (44,136) |
| Intangible lease liabilities, net | 186,935 | 193,903 |
| In-Place Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease assets, gross | 640,108 | 649,182 |
| Above-Market Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease assets, gross | 90,645 | 98,056 |
| Below-Market Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease liabilities, gross | $ 237,667 | $ 238,039 |