Contracts with customers (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Rental Revenue
Future minimum lease payments to be received under noncancelable leases
2018	$ 192,453
2019	197,753
2020	136,461
2021	103,176
2022	78,777
Thereafter	168,500
Total	877,120
Power Revenue \| ASU 2014-09
Future minimum lease payments to be received under noncancelable leases
2018	48,559
2019	35,425
2020	17,688
2021	7,481
2022	2,684
Thereafter	2,763
Total	$ 114,600

Amount of lease payments to be received by lessor for operating lease.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

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+ References

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+ References

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Amount of lease payments to be received by lessor in third fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

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