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Consolidated Statements of Comprehensive Income - Parenthetical - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Net unrealized gain (loss) on derivative instruments arising during the period, tax | $ 0 | $ 0 | $ (3,116)
Reclassification adjustment for (gain) loss on derivative instruments included in net income, tax | 233 | 240 | 339
Reclassification adjustment for (gain) loss on derivative instruments included in discontinued operations, tax | 0 | 173 | (2,887)
Postretirement liability gains (losses) arising during the period, tax | (55) | (7,665) | 11,818
Amortization of postretirement liability losses included in net periodic benefit cost (credit), tax | 1,128 | 492 | 1,276
Reclassification of postretirement liability adjustment to regulatory asset, tax | 1,416 | 4,509 | 0
Foreign currency translation adjustment recognized during the period, tax | (105) | (99) | (177)
Reclassification adjustment for (gain) loss on foreign currency translation adjustment included in net income, tax | 490 | 0 | 70
Net unrealized gains (losses) on available-for-sale investments arising during the period, tax | (91) | (83) | (105)
Reclassification adjustments for (gain) loss on available-for-sale investments included in net income, tax | $ 70 | $ 73 | $ 59

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- Definition Amount of tax expense (benefit), before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6915805&loc=d3e32211-110900 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580 + Details
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- Definition Amount of tax (expense) benefit, before reclassification adjustments, related to (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement benefit plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580 + Details
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