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Property, plant and equipment - Schedule of Plant, Property and Equipment (Detail) - CAD CAD in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Property, Plant and Equipment [Line Items] |  |
Cost | CAD 8,938,776 | CAD 5,816,327
Accumulated depreciation | 1,029,283 | 926,381
Net book value | 7,909,493 | 4,889,946
Land |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 89,935 | 60,868
Accumulated depreciation | 0 | 0
Net book value | 89,935 | 60,868
Equipment and other |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 143,158 | 139,961
Accumulated depreciation | 51,026 | 44,700
Net book value | 92,132 | 95,261
Generation |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 2,988,569 | 2,613,267
Accumulated depreciation | 494,912 | 419,227
Net book value | 2,493,657 | 2,194,040
Generation | Construction in progress |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 263,418 | 197,405
Accumulated depreciation | 0 | 0
Net book value | 263,418 | 197,405
Liberty Utilities Group |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 5,247,499 | 2,638,488
Accumulated depreciation | 483,345 | 462,454
Net book value | 4,764,154 | 2,176,034
Liberty Utilities Group | Construction in progress |  |
Property, Plant and Equipment [Line Items] |  |
Cost | 206,197 | 166,338
Accumulated depreciation | 0 | 0
Net book value | CAD 206,197 | CAD 166,338

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- Definition Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(13)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(14)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(8)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
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