Finite-Lived Intangible Assets and Liabilities and Goodwill (Tables)
 6 Months Ended
Jun. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]  
Schedule Of Finite Lived Intangible Assets and Liability
The following presents the major components of the finite-lived intangible assets and liabilities (in thousands):
 
 
June 30, 2018
 
 
Weighted Average Remaining Life
 
Gross
 
Accumulated Amortization
 
Net
Intangible assets
 
 
 
 
 
 
 
 
Power purchase agreements
 
16
 
$
224,528

 
$
(23,161
)
 
$
201,367

Industrial revenue bond tax savings
 
24
 
12,778

 
(611
)
 
12,167

Other intangible assets
 
33
 
13,898

 
(1,075
)
 
12,823

Leasehold interest
 
8
 
$
67

 
$
(2
)
 
$
65

Total intangible assets
 
 
 
$
251,271

 
$
(24,849
)
 
$
226,422

Intangible liabilities
 
 
 
 
 
 
 
 
Power purchase agreement
 
14
 
$
60,300

 
$
(10,840
)
 
$
49,460

Leasehold interest
 
23
 
8,858

 
(123
)
 
8,735

Total intangible liabilities
 
 
 
$
69,158

 
$
(10,963
)
 
$
58,195


 
 
December 31, 2017
 
 
Weighted Average Remaining Life
 
Gross
 
Accumulated Amortization
 
Net
Intangible assets
 
 
 
 
 
 
 
 
Power purchase agreement
 
15
 
$
127,084

 
$
(17,611
)
 
$
109,473

Industrial revenue bond tax savings
 
24
 
12,778

 
(351
)
 
12,427

Other intangible assets
 
34
 
15,234

 
(1,086
)
 
14,148

Total intangible assets
 
 
 
$
155,096

 
$
(19,048
)
 
$
136,048

Intangible liability
 
 
 
 
 
 
 
 
Power purchase agreement
 
15
 
$
60,300

 
$
(9,106
)
 
$
51,194
Finite-lived Intangible Assets Amortization Expense
The following table presents estimated future amortization for the next five years related to the Company's finite-lived intangible assets and liabilities (in thousands):
Year ended December 31,
 
Power purchase agreements, net
 
Industrial revenue bond tax savings
 
Other intangible assets
 
Leasehold interests
2018 (remainder)
 
$
4,874

 
$
256

 
$
278

 
$
(189
)
2019
 
9,748

 
512

 
556

 
(379
)
2020
 
9,748

 
512

 
556

 
(379
)
2021
 
9,748

 
512

 
556

 
(379
)
2022
 
9,748

 
512

 
556

 
(379
)
Thereafter
 
108,092

 
9,862

 
10,278

 
(6,968
)
Schedule of Goodwill
The following table presents a reconciliation of the beginning and ending carrying amounts of goodwill (in millions):
 
 
Total
Balances at December 31, 2017
 
$
—

Net additions during the period(1)
 
60.3

Balances at March 31, 2018
 
$
60.3

Foreign currency translation adjustment
 
(2.6
)
Balances at June 30, 2018
 
$
57.7

(1) 
The Company recorded goodwill on March 7, 2018 as a result of the Japan Acquisition.