Investments
 12 Months Ended
Dec. 31, 2017
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]  
Investments
Investments
Real Estate Investments
As of December 31, 2017, the Company’s gross investment in real estate properties and loans totaled approximately $7.90 billion, representing investments in 2,480 properties, including 88 properties or other related assets securing mortgage loans. The gross investment is comprised of land, buildings, lease intangible assets and lease intangible liabilities, as adjusted for any impairment, and the carrying amount of loans receivable, real estate assets held under direct financing leases and real estate assets held for sale. The portfolio is geographically dispersed throughout 49 states with only one state, Texas, with a real estate investment of 12.2%, accounting for more than 10.0% of the total dollar amount of the Company’s real estate investment portfolio.
During the years ended December 31, 2017 and 2016, the Company had the following real estate and loan activity, net of accumulated depreciation and amortization:
 
Number of Properties
 
Dollar Amount of Investments
 
Owned
 
Financed
 
Total
 
Owned
 
Financed
 
Total
 
 
 
 
 
 

 
(In Thousands)
Gross balance, December 31, 2015
2,485

 
144

 
2,629

 
$
8,198,685

 
$
104,003

 
$
8,302,688

Acquisitions/improvements (1)
269

 
—

 
269

 
711,510

 
—

 
711,510

Dispositions of real estate (2)(3)
(213
)
 
—

 
(213
)
 
(598,662
)
 
—

 
(598,662
)
Principal payments and payoffs
—

 
(70
)
 
(70
)
 
—

 
(34,955
)
 
(34,955
)
Impairments
—

 
—

 
—

 
(88,073
)
 
(176
)
 
(88,249
)
Write-off of gross lease intangibles
—

 
—

 
—

 
(42,307
)
 
—

 
(42,307
)
Loan premium amortization and other
—

 
—

 
—

 
(77
)
 
(2,294
)
 
(2,371
)
Gross balance, December 31, 2016
2,541

 
74

 
2,615

 
8,181,076

 
66,578

 
8,247,654

Acquisitions/improvements (1)
43

 
16

 
59

 
326,766

 
23,300

 
350,066

Dispositions of real estate (2)(3)
(192
)
 
—

 
(192
)
 
(510,863
)
 
—

 
(510,863
)
Principal payments and payoffs
—

 
(2
)
 
(2
)
 
—

 
(7,878
)
 
(7,878
)
Impairments
—

 
—

 
—

 
(101,941
)
 
(389
)
 
(102,330
)
Write-off of gross lease intangibles
—

 
—

 
—

 
(67,139
)
 
—

 
(67,139
)
Loan premium amortization and other
—

 
—

 
—

 
(4,841
)
 
(1,644
)
 
(6,485
)
Gross balance, December 31, 2017
2,392

 
88

 
2,480

 
$
7,823,058

 
$
79,967

 
$
7,903,025

Accumulated depreciation and amortization
 
 
 
 
 
 
(1,289,304
)
 
—

 
(1,289,304
)
Other
 
 
 
 
 
 
304

 
—

 
304

Net balance, December 31, 2017
 
 
 
 
 
 
$
6,534,058

 
$
79,967

 
$
6,614,025


(1) 
Includes investments of $42.6 million and $20.5 million, respectively, in revenue producing capitalized expenditures, as well as $3.5 million and $6.6 million, respectively, of non-revenue producing capitalized expenditures for the years ended December 31, 2017 and 2016.
(2) 
The total accumulated depreciation and amortization associated with dispositions of real estate was $57.1 million and $126.4 million, respectively, for the years ended December 31, 2017 and 2016.
(3) 
For the years ended December 31, 2017, 2016 and 2015 the total gain on disposal of assets for properties held in use and held for sale was $24.6 million and $40.5 million, $35.8 million and $16.6 million, and $34.5 million and $33.9 million, respectively.

Scheduled minimum future contractual rent to be received under the remaining non-cancelable term of the operating leases (including realized rent increases occurring after January 1, 2018) are as follows (in thousands):
 
December 31,
2017
2018
$
599,194

2019
587,493

2020
570,820

2021
542,899

2022
507,936

Thereafter
3,637,342

Total future minimum rentals
$
6,445,684


Because lease renewal periods are exercisable at the option of the lessee, the preceding table presents future minimum lease payments due during the initial lease term only. In addition, the future minimum rentals do not include any contingent rentals based on a percentage of the lessees’ gross sales or lease escalations based on future changes in the CPI or other stipulated reference rate.
Loans Receivable
The following table details loans receivable, net of premium and allowance for loan losses (in thousands):
 
December 31,
2017
 
December 31,
2016
Mortgage loans - principal
$
69,963

 
$
55,410

Mortgage loans - premium, net of amortization
5,038

 
7,194

Allowance for loan losses
(389
)
 
—

    Mortgages loans, net
74,612

 
62,604

Other note receivables - principal
5,355

 
4,474

Allowance for loan losses
—

 
(500
)
     Other note receivables
5,355

 
3,974

Total loans receivable, net
$
79,967

 
$
66,578


As of December 31, 2017 and 2016, the Company held a total of 10 and 8, respectively, first-priority mortgage loans (representing loans to 6 and 4 borrowers, respectively). These mortgage loans are secured by single-tenant commercial properties and generally have fixed interest rates over the term of the loans. There are 3 other notes receivable, one $3.5 million note is secured by tenant assets and stock and the other two are unsecured.
Lease Intangibles, Net
The following table details lease intangible assets and liabilities, net of accumulated amortization (in thousands):
 
December 31,
2017
 
December 31,
2016
In-place leases
$
591,551

 
$
624,723

Above-market leases
89,640

 
88,873

Less: accumulated amortization
(271,288
)
 
(243,320
)
Intangible lease assets, net
$
409,903

 
$
470,276

 
 
 
 
Below-market leases
$
216,642

 
$
236,008

Less: accumulated amortization
(61,339
)
 
(53,688
)
Intangible lease liabilities, net
$
155,303

 
$
182,320


The amounts amortized as a net increase to rental revenue for capitalized above and below-market leases was $6.5 million, $6.6 million and $5.8 million for the years ended December 31, 2017, 2016 and 2015, respectively. The value of in-place leases amortized and included in depreciation and amortization expense was $43.3 million, $46.4 million and $49.9 million for the years ended December 31, 2017, 2016 and 2015, respectively. The remaining weighted average amortization period for in-place leases, above-market leases, below-market leases and in total was 13.8 years 9.5 years, 17.5 years and 10.6 years, respectively, as of December 31, 2017. The remaining weighted average amortization period for in-place leases, above-market leases, below-market leases and in total was 14.6 years, 10.3 years, 18.5 years and 11.2 years, respectively, as of December 31, 2016. During the year ended December 31, 2017, the Company acquired in-place lease intangible assets of $18.7 million, above-market lease intangible assets of $6.5 million and below-market lease intangible liabilities of $2.0 million.
Based on the balance of intangible assets and liabilities at December 31, 2017, the net aggregate amortization expense for the next five years and thereafter is expected to be as follows (in thousands):
2018
$
32,343

2019
30,736

2020
28,717

2021
26,108

2022
22,838

Thereafter
113,858

Total future minimum amortization
$
254,600


Real Estate Assets Under Direct Financing Leases
The components of real estate investments held under direct financing leases were as follows (in thousands):
 
December 31,
2017
 
December 31, 2016
Minimum lease payments receivable
$
7,325

 
$
9,456

Estimated residual value of leased assets
24,552

 
35,640

Unearned income
(7,012
)
 
(9,091
)
Real estate assets under direct financing leases, net
$
24,865

 
$
36,005

Real Estate Assets Held for Sale
The Company is continually evaluating the portfolio of real estate assets and may elect to dispose of assets considering criteria including, but not limited to, tenant concentration, tenant credit quality, unit financial performance, local market conditions and lease rates, associated indebtedness, asset location, and tenant operation type (e.g., industry, sector, or concept/brand). Real estate assets held for sale are expected to be sold within twelve months. The following table shows the activity in real estate assets held for sale, net for the years ended December 31, 2017 and 2016:
 
Number of Properties
 
Carrying Value
 
(In Thousands)
Balance, December 31, 2015
36

 
$
84,259

Transfers from real estate investments
72

 
246,730

Sales
(59
)
 
(126,100
)
Transfers to real estate investments held and used
(5
)
 
(21,046
)
Impairments
—

 
(23,273
)
Balance, December 31, 2016
44

 
160,570

Transfers from real estate investments
82

 
216,502

Sales
(91
)
 
(208,029
)
Transfers to real estate investments held and used
(20
)
 
(95,382
)
Impairments
—

 
(24,732
)
Balance, December 31, 2017
15

 
$
48,929


Impairments
The following table summarizes total impairment losses recognized in continuing and discontinued operations on the accompanying consolidated statements of operations (in thousands): 
 
Years Ended December 31,
 
2017
 
2016
 
2015
Real estate and intangible asset impairment
$
93,441

 
$
80,390

 
$
68,565

Write-off of lease intangibles, net
8,500

 
7,683

 
1,666

Loans receivable impairment
389

 
176

 
324

Total impairments from real estate investment net assets
102,330

 
88,249

 
70,555

Other impairment
—

 
26

 
174

Total impairment loss in continuing and discontinued operations
$
102,330

 
$
88,275

 
$
70,729


Impairments for the twelve months ended December 31, 2017 were comprised of $24.8 million on properties classified as held for sale and $77.2 million properties classified a held and used. Impairments for the twelve months ended December 31, 2016 were comprised of $23.1 million on properties held for sale and $47.2 million on properties classified as held and used. Impairments for the twelve months ended December 31, 2015 were comprised of $15.0 million on properties held for sale and $55.4 million on properties classified as held and used.