Investments - Schedule of Lease Intangible Assets and Liabilities, Net of Accumulated Amortization (Details) - USD ($) $ in Thousands |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Capital Leased Assets [Line Items] | ||
| Less: accumulated amortization | $ (248,828) | $ (243,320) |
| Intangible lease assets, net | 459,799 | 470,276 |
| Less: accumulated amortization | (55,135) | (53,688) |
| Intangible lease liabilities, net | 175,261 | 182,320 |
| In-Place Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease assets, gross | 621,372 | 624,723 |
| Above-Market Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease assets, gross | 87,255 | 88,873 |
| Below-Market Leases | ||
| Capital Leased Assets [Line Items] | ||
| Intangible lease liabilities, gross | $ 230,396 | $ 236,008 |