Investments - Additional Information (Details)
$ in Thousands |
12 Months Ended |
|
Dec. 31, 2017
USD ($)
loan
State
Property
borrower
|
Dec. 31, 2016
USD ($)
loan
Property
borrower
|
Dec. 31, 2015
USD ($)
Property
|
| Investment [Line Items] |
|
|
|
| Real estate properties and loans, gross |
$ 7,903,025
|
$ 8,247,654
|
$ 8,302,688
|
| Number of real estate properties invested in | Property |
2,480
|
2,615
|
2,629
|
| Number of states properties dispersed geographically | State |
49
|
|
|
| Number of states exceeding disclosure threshold | State |
1
|
|
|
| Minimum percentage of investment in real estate properties |
10.00%
|
|
|
| Number of notes receivable (in loans) | loan |
3
|
|
|
| Amortization amount to rental revenue for capitalized leases |
$ 6,500
|
$ 6,600
|
$ 5,800
|
| Leases amortization expenses |
43,300
|
46,400
|
49,900
|
| Below market lease acquired |
$ 2,000
|
|
|
| Real estate assets held-for-sale expected selling period |
12 months
|
|
|
| Impairment of properties classified as held for sale |
$ 24,800
|
23,100
|
15,000
|
| Impairment of properties classified as held and used |
$ 77,200
|
$ 47,200
|
55,400
|
| In-place Leases |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
13 years 9 months 18 days
|
14 years 7 months 6 days
|
|
| Acquired finite-lived intangible assets |
$ 18,700
|
|
|
| Above market leases |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
9 years 6 months
|
10 years 3 months 18 days
|
|
| Acquired finite-lived intangible assets |
$ 6,500
|
|
|
| Below-market Leases |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
17 years 6 months
|
|
|
| Below-market Leases | Minimum |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
|
18 years 6 months
|
|
| Below-market Leases | Maximum |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
|
11 years 2 months 12 days
|
|
| Leases |
|
|
|
| Investment [Line Items] |
|
|
|
| Lease intangibles weighted average amortization period |
10 years 7 months 6 days
|
|
|
| Single-Tenant Commercial Properties | First Mortgage |
|
|
|
| Investment [Line Items] |
|
|
|
| Number of first-priority mortgage loans | loan |
10
|
8
|
|
| Number of borrowers | borrower |
6
|
4
|
|
| Tenant Assets and Stock |
|
|
|
| Investment [Line Items] |
|
|
|
| Number of notes receivable (in loans) | loan |
1
|
|
|
| Secured notes receivable, net |
$ 3,500
|
|
|
| Unsecured |
|
|
|
| Investment [Line Items] |
|
|
|
| Number of notes receivable (in loans) | loan |
2
|
|
|
| Texas |
|
|
|
| Investment [Line Items] |
|
|
|
| Percentage of investment in real estate properties |
12.20%
|
|
|
| Financed Properties |
|
|
|
| Investment [Line Items] |
|
|
|
| Real estate properties and loans, gross |
$ 79,967
|
$ 66,578
|
$ 104,003
|
| Number of real estate properties invested in | Property |
88
|
74
|
144
|