Document and Entity Information
Document and Entity Information - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Feb. 15, 2018 | Jun. 30, 2017 | |
Document And Entity Information [Abstract] | |||
Document Type | 10-K | ||
Amendment Flag | false | ||
Document Period End Date | Dec. 31, 2017 | ||
Document Fiscal Year Focus | 2,017 | ||
Document Fiscal Period Focus | FY | ||
Trading Symbol | SWX | ||
Entity Registrant Name | SOUTHWEST GAS HOLDINGS, INC. | ||
Entity Central Index Key | 1,692,115 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity Well-known Seasoned Issuer | Yes | ||
Entity Current Reporting Status | Yes | ||
Entity Voluntary Filers | No | ||
Entity Filer Category | Large Accelerated Filer | ||
Entity Common Stock, Shares Outstanding | 48,159,162 | ||
Entity Public Float | $ 3,476,422,674 |
Consolidated Balance Sheets
Consolidated Balance Sheets - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Utility plant: | ||
Gas plant | $ 6,629,644 | $ 6,193,760 |
Less: accumulated depreciation | (2,231,242) | (2,172,966) |
Construction work in progress | 125,248 | 111,177 |
Net utility plant (Note 2) | 4,523,650 | 4,131,971 |
Other property and investments (Note 1) | 428,180 | 342,343 |
Current assets: | ||
Cash and cash equivalents | 43,622 | 28,066 |
Accounts receivable, net of allowances (Note 4) | 347,375 | 285,145 |
Accrued utility revenue (Note 3) | 78,200 | 76,200 |
Income taxes receivable, net | 7,960 | 4,455 |
Deferred purchased gas costs (Note 5) | 14,581 | 2,608 |
Prepaids and other current assets (Notes 1, 5, and 14) | 165,294 | 136,833 |
Total current assets | 657,032 | 533,307 |
Noncurrent assets: | ||
Goodwill (Note 1) | 179,314 | 139,983 |
Deferred income taxes (Note 13) | 1,480 | 1,288 |
Deferred charges and other assets (Notes 2, 5, and 14) | 447,410 | 432,234 |
Total noncurrent assets | 628,204 | 573,505 |
Total assets | 6,237,066 | 5,581,126 |
Capitalization: | ||
Common stock | 49,720 | 49,112 |
Additional paid-in capital | 955,332 | 903,123 |
Accumulated other comprehensive income (loss), net (Note 6) | (47,682) | (48,008) |
Retained earnings | 857,398 | 759,263 |
Total Southwest Gas Holdings, Inc. equity | 1,814,768 | 1,663,490 |
Noncontrolling interest | (2,365) | (2,217) |
Total equity | 1,812,403 | 1,661,273 |
Redeemable noncontrolling interest (Note 17) | 22,590 | |
Long-term debt, less current maturities (Note 8) | 1,798,576 | 1,549,983 |
Total capitalization | 3,610,979 | 3,233,846 |
Commitments and contingencies (Note 10) | ||
Current liabilities: | ||
Current maturities of long-term debt (Note 8) | 25,346 | 50,101 |
Short-term debt (Note 9) | 214,500 | |
Accounts payable | 228,315 | 184,669 |
Customer deposits | 69,781 | 72,296 |
Income taxes payable, net | 5,946 | 1,909 |
Accrued general taxes | 43,879 | 42,921 |
Accrued interest | 17,870 | 17,939 |
Deferred purchased gas costs (Note 5) | 6,841 | 90,476 |
Other current liabilities (Notes 2, 5, and 14) | 203,403 | 168,064 |
Total current liabilities | 815,881 | 628,375 |
Deferred income taxes and other credits: | ||
Deferred income taxes and investment tax credits, net (Note 13) | 476,960 | 840,653 |
Accumulated removal costs (Note 5) | 315,000 | 308,000 |
Other deferred credits and other long-term liabilities (Notes 2, 5, 11, and 14) | 1,018,246 | 570,252 |
Total deferred income taxes and other credits | 1,810,206 | 1,718,905 |
Total capitalization and liabilities | 6,237,066 | 5,581,126 |
Southwest Gas Corporation [Member] | ||
Utility plant: | ||
Gas plant | 6,629,644 | 6,193,760 |
Less: accumulated depreciation | (2,231,242) | (2,172,966) |
Construction work in progress | 125,248 | 111,177 |
Net utility plant (Note 2) | 4,523,650 | 4,131,971 |
Other property and investments (Note 1) | 119,114 | 108,569 |
Current assets: | ||
Cash and cash equivalents | 37,946 | 19,024 |
Accounts receivable, net of allowances (Note 4) | 119,748 | 111,845 |
Accrued utility revenue (Note 3) | 78,200 | 76,200 |
Income taxes receivable, net | 4,455 | |
Deferred purchased gas costs (Note 5) | 14,581 | 2,608 |
Prepaids and other current assets (Notes 1, 5, and 14) | 153,771 | 126,363 |
Total current assets | 404,246 | 340,495 |
Noncurrent assets: | ||
Goodwill (Note 1) | 10,095 | 10,095 |
Deferred charges and other assets (Notes 2, 5, and 14) | 425,564 | 410,625 |
Discontinued operations - construction services - assets (Note 18) | 579,371 | |
Total noncurrent assets | 435,659 | 1,000,091 |
Total assets | 5,482,669 | 5,581,126 |
Capitalization: | ||
Common stock | 49,112 | 49,112 |
Additional paid-in capital | 948,767 | 897,346 |
Accumulated other comprehensive income (loss), net (Note 6) | (47,073) | (45,639) |
Retained earnings | 659,193 | 767,061 |
Total Southwest Gas Holdings, Inc. equity | 1,609,999 | 1,667,880 |
Discontinued operations - construction services non-owner equity | 15,983 | |
Long-term debt, less current maturities (Note 8) | 1,521,031 | 1,375,080 |
Total capitalization | 3,131,030 | 3,058,943 |
Commitments and contingencies (Note 10) | ||
Current liabilities: | ||
Current maturities of long-term debt (Note 8) | 25,000 | |
Short-term debt (Note 9) | 191,000 | |
Accounts payable | 158,474 | 138,229 |
Customer deposits | 69,781 | 72,296 |
Income taxes payable, net | 4,971 | |
Accrued general taxes | 43,879 | 42,921 |
Accrued interest | 17,171 | 17,395 |
Deferred purchased gas costs (Note 5) | 6,841 | 90,476 |
Payable to parent | 194 | |
Other current liabilities (Notes 2, 5, and 14) | 108,785 | 95,999 |
Total current liabilities | 601,096 | 482,316 |
Deferred income taxes and other credits: | ||
Deferred income taxes and investment tax credits, net (Note 13) | 445,243 | 806,109 |
Accumulated removal costs (Note 5) | 315,000 | 308,000 |
Other deferred credits and other long-term liabilities (Notes 2, 5, 11, and 14) | 990,300 | 545,143 |
Discontinued operations - construction services - liabilities (Note 18) | 380,615 | |
Total deferred income taxes and other credits | 1,750,543 | 2,039,867 |
Total capitalization and liabilities | $ 5,482,669 | $ 5,581,126 |
Consolidated Balance Sheets (Pa
Consolidated Balance Sheets (Parenthetical) - $ / shares | Dec. 31, 2017 | Dec. 31, 2016 |
Statement of Financial Position [Abstract] | ||
Common stock, par | $ 1 | $ 1 |
Common stock, authorized | 60,000,000 | 60,000,000 |
Common stock, issued | 48,090,470 | 47,482,068 |
Common stock, outstanding | 48,090,470 | 47,482,068 |
Consolidated Statements of Inco
Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Operating revenues: | |||
Gas operating revenues (Note 3) | $ 1,302,308 | $ 1,321,412 | $ 1,454,639 |
Construction revenues (Note 3) | 1,246,484 | 1,139,078 | 1,008,986 |
Total operating revenues | 2,548,792 | 2,460,490 | 2,463,625 |
Gas operating revenues (Note 3) | 1,302,308 | 1,321,412 | 1,454,639 |
Operating expenses: | |||
Net cost of gas sold | 355,045 | 397,121 | 563,809 |
Operations and maintenance | 412,187 | 401,724 | 393,199 |
Depreciation and amortization | 250,951 | 289,132 | 270,111 |
Taxes other than income taxes | 57,946 | 52,376 | 49,393 |
Construction expenses | 1,148,963 | 1,024,423 | 898,781 |
Total operating expenses | 2,225,092 | 2,164,776 | 2,175,293 |
Operating income | 323,700 | 295,714 | 288,332 |
Other income and (expenses): | |||
Net interest deductions (Notes 8 and 9) | (78,064) | (73,660) | (71,879) |
Other income (deductions) | 13,394 | 9,469 | 2,879 |
Total other income and (expenses) | (64,670) | (64,191) | (69,000) |
Income before income taxes | 259,030 | 231,523 | 219,332 |
Income tax expense (Note 13) | 65,088 | 78,468 | 79,902 |
Net income | 193,942 | 153,055 | 139,430 |
Net income attributable to noncontrolling interests | 101 | 1,014 | 1,113 |
Net income | $ 193,841 | $ 152,041 | $ 138,317 |
Basic earnings per share (Notes 1 and 16) | $ 4.04 | $ 3.20 | $ 2.94 |
Diluted earnings per share (Notes 1 and 16) | $ 4.04 | $ 3.18 | $ 2.92 |
Average number of common shares | 47,965 | 47,469 | 46,992 |
Average shares (assuming dilution) | 47,991 | 47,814 | 47,383 |
Southwest Gas Corporation [Member] | |||
Operating revenues: | |||
Gas operating revenues (Note 3) | $ 1,302,308 | $ 1,321,412 | $ 1,454,639 |
Gas operating revenues (Note 3) | 1,302,308 | 1,321,412 | 1,454,639 |
Operating expenses: | |||
Net cost of gas sold | 355,045 | 397,121 | 563,809 |
Operations and maintenance | 410,745 | 401,724 | 393,199 |
Depreciation and amortization | 201,922 | 233,463 | 213,455 |
Taxes other than income taxes | 57,946 | 52,376 | 49,393 |
Total operating expenses | 1,025,658 | 1,084,684 | 1,219,856 |
Operating income | 276,650 | 236,728 | 234,783 |
Other income and (expenses): | |||
Net interest deductions (Notes 8 and 9) | (69,733) | (66,997) | (64,095) |
Other income (deductions) | 13,036 | 8,276 | 2,292 |
Total other income and (expenses) | (56,697) | (58,721) | (61,803) |
Income before income taxes | 219,953 | 178,007 | 172,980 |
Income tax expense (Note 13) | 63,135 | 58,584 | 61,355 |
Net income | 156,818 | 153,055 | 139,430 |
Net income (loss) from continuing operations | 156,818 | 119,423 | 111,625 |
Discontinued operations-construction services, income before income taxes | 53,516 | 46,352 | |
Discontinued operations-construction services, Income tax expense | 19,884 | 18,547 | |
Discontinued operations-construction services, Income | 33,632 | 27,805 | |
Discontinued operations-construction services - Noncontrolling interests | 1,014 | 1,113 | |
Income - discontinued operations | 32,618 | 26,692 | |
Net income | $ 156,818 | $ 152,041 | $ 138,317 |
Condensed Consolidated Statemen
Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Net Income | $ 193,942 | $ 153,055 | $ 139,430 |
Defined benefit pension plans (Notes 6 and 11): | |||
Net actuarial gain (loss) | (32,701) | (14,118) | (18,922) |
Amortization of prior service cost | 828 | 828 | 828 |
Amortization of net actuarial loss | 15,776 | 16,781 | 21,316 |
Regulatory adjustment | 12,590 | (3,462) | (3,500) |
Net defined benefit pension plans | (3,507) | 29 | (278) |
Forward-starting interest rate swaps: | |||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
Net forward-starting interest rate swaps | 2,073 | 2,075 | 2,073 |
Foreign currency translation adjustments | 1,771 | 161 | (1,954) |
Total other comprehensive income (loss), net of tax | 337 | 2,265 | (159) |
Comprehensive income | 194,279 | 155,320 | 139,271 |
Comprehensive income attributable to noncontrolling interests | 112 | 1,019 | 1,047 |
Comprehensive income | 194,167 | 154,301 | 138,224 |
Southwest Gas Corporation [Member] | |||
Net Income from continuing operations | 156,818 | 119,423 | 111,625 |
Net Income | 156,818 | 153,055 | 139,430 |
Defined benefit pension plans (Notes 6 and 11): | |||
Net actuarial gain (loss) | (32,701) | (14,118) | (18,922) |
Amortization of prior service cost | 828 | 828 | 828 |
Amortization of net actuarial loss | 15,776 | 16,781 | 21,316 |
Regulatory adjustment | 12,590 | (3,462) | (3,500) |
Net defined benefit pension plans | (3,507) | 29 | (278) |
Forward-starting interest rate swaps: | |||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
Net forward-starting interest rate swaps | 2,073 | 2,075 | 2,073 |
Total other comprehensive income (loss), net of tax | (1,434) | 2,104 | 1,795 |
Comprehensive income | 155,384 | 121,527 | 113,420 |
Discontinued operations-construction services, net income | 32,618 | 26,692 | |
Discontinued operations-construction services, foreign currency translation adjustments | 161 | (1,954) | |
Discontinued operations-construction services, comprehensive income | 32,779 | 24,738 | |
Discontinued operations-construction services, comprehensive income (loss) attributable to noncontrolling interests | 5 | (66) | |
Comprehensive income attributable to discontinued operations - construction services | 32,774 | 24,804 | |
Comprehensive income | $ 155,384 | $ 154,301 | $ 138,224 |
Consolidated Statements of Cash
Consolidated Statements of Cash Flows - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
CASH FLOW FROM OPERATING ACTIVITIES: | |||
Net Income | $ 193,942 | $ 153,055 | $ 139,430 |
Adjustments to reconcile net income to net cash provided by operating activities: | |||
Depreciation and amortization | 250,951 | 289,132 | 270,111 |
Deferred income taxes | 63,389 | 68,732 | 48,785 |
Changes in current assets and liabilities: | |||
Accounts receivable, net of allowances | (40,947) | 30,096 | (39,850) |
Accrued utility revenue | (2,000) | (1,500) | (800) |
Deferred purchased gas costs | (95,608) | 45,858 | 129,566 |
Accounts payable | 19,961 | 21,695 | (3,491) |
Accrued taxes | 2,112 | 26,340 | (8,405) |
Other current assets and liabilities | (8,203) | (27,432) | 23,213 |
Gains on sale | (4,196) | (7,148) | (3,102) |
Changes in undistributed stock compensation | 10,888 | 5,456 | 2,914 |
AFUDC | (2,296) | (2,289) | (3,008) |
Changes in other assets and deferred charges | (22,269) | 16,960 | (14,166) |
Changes in other liabilities and deferred credits | 4,231 | (18,447) | 10,863 |
Net cash provided by operating activities | 369,955 | 600,508 | 552,060 |
CASH FLOW FROM INVESTING ACTIVITIES: | |||
Construction expenditures and property additions | (623,649) | (529,531) | (488,000) |
Acquisition of businesses, net of cash acquired | (94,204) | (17,000) | (9,261) |
Restricted cash | 785 | ||
Changes in customer advances | 323 | 7,900 | 18,300 |
Miscellaneous inflows | 16,645 | 13,039 | 8,354 |
Net cash used in investing activities | (700,885) | (525,592) | (469,822) |
CASH FLOW FROM FINANCING ACTIVITIES: | |||
Issuance of common stock, net | 41,155 | 472 | 35,396 |
Dividends paid | (92,130) | (83,317) | (74,248) |
Centuri distribution to redeemable noncontrolling interest | (204) | (439) | (99) |
Issuance of long-term debt, net | 407,063 | 423,946 | 135,816 |
Retirement of long-term debt | (338,969) | (255,273) | (187,973) |
Change in credit facility and commercial paper | 145,000 | (145,000) | |
Change in short-term debt | 214,500 | (18,000) | 13,000 |
Principal payments on capital lease obligations | (980) | (1,354) | (1,420) |
Redemption of Centuri shares from noncontrolling parties | (23,000) | ||
Withholding remittance - share-based compensation | (3,176) | (2,119) | (4,913) |
Other | (3,074) | (1,569) | 41 |
Net cash provided by (used in) financing activities | 346,185 | (82,653) | (84,400) |
Effects of currency translation on cash and cash equivalents | 301 | (194) | (1,407) |
Change in cash and cash equivalents | 15,556 | (7,931) | (3,569) |
Cash and cash equivalents at beginning of period | 28,066 | 35,997 | 39,566 |
Cash and cash equivalents at end of period | 43,622 | 28,066 | 35,997 |
Supplemental information: | |||
Interest paid, net of amounts capitalized | 71,943 | 67,440 | 66,623 |
Income taxes paid (received) | 5,673 | (19,032) | 43,225 |
Southwest Gas Corporation [Member] | |||
CASH FLOW FROM OPERATING ACTIVITIES: | |||
Net Income | 156,818 | 153,055 | 139,430 |
Income (loss) from discontinued operations | 33,632 | 27,805 | |
Net income (loss) from continuing operations | 156,818 | 119,423 | 111,625 |
Adjustments to reconcile net income to net cash provided by operating activities: | |||
Depreciation and amortization | 201,922 | 233,463 | 213,455 |
Deferred income taxes | 67,169 | 67,959 | 53,396 |
Changes in current assets and liabilities: | |||
Accounts receivable, net of allowances | (7,902) | 40,731 | (12,444) |
Accrued utility revenue | (2,000) | (1,500) | (800) |
Deferred purchased gas costs | (95,608) | 45,858 | 129,566 |
Accounts payable | 4,545 | 16,183 | (8,751) |
Accrued taxes | 10,383 | 19,391 | (1,626) |
Other current assets and liabilities | (13,726) | (33,496) | 21,736 |
Changes in undistributed stock compensation | 9,288 | 5,456 | 2,914 |
AFUDC | (2,296) | (2,289) | (3,008) |
Changes in other assets and deferred charges | (22,918) | 16,611 | (14,513) |
Changes in other liabilities and deferred credits | 3,541 | (18,447) | 10,863 |
Net cash provided by operating activities | 309,216 | 509,343 | 502,413 |
CASH FLOW FROM INVESTING ACTIVITIES: | |||
Construction expenditures and property additions | (560,448) | (457,119) | (438,289) |
Changes in customer advances | 323 | 7,900 | 18,300 |
Miscellaneous inflows | 2,741 | 2,982 | 3,262 |
Dividends received | 12,461 | 2,801 | |
Net cash used in investing activities | (557,384) | (433,776) | (413,926) |
CASH FLOW FROM FINANCING ACTIVITIES: | |||
Issuance of common stock, net | 472 | 35,396 | |
Contributions from parent | 41,359 | ||
Dividends paid | (81,497) | (83,317) | (74,248) |
Issuance of long-term debt, net | 296,469 | ||
Retirement of long-term debt | (25,000) | (124,855) | (51,200) |
Change in credit facility and commercial paper | 145,000 | (145,000) | |
Change in short-term debt | 191,000 | (18,000) | 13,000 |
Withholding remittance - share-based compensation | (3,176) | (2,119) | (4,913) |
Other | (596) | (1,569) | 92 |
Net cash provided by (used in) financing activities | 267,090 | (77,919) | (81,873) |
Net cash provided by discontinued operating activities | 91,165 | 49,647 | |
Net cash used in discontinued investing activities | (91,816) | (55,896) | |
Net cash provided by (used in) discontinued financing activities | (4,734) | (2,527) | |
Effects of currency translation on cash and cash equivalents | (194) | (1,407) | |
Change in cash and cash equivalents | 18,922 | (7,931) | (3,569) |
Change in cash and cash equivalents of discontinued operations included in discontinued operations construction services assets | 5,579 | 10,183 | |
Change in cash and cash equivalents of continuing operations | 18,922 | (2,352) | 6,614 |
Cash and cash equivalents at beginning of period | 19,024 | 21,376 | 14,762 |
Cash and cash equivalents at end of period | 37,946 | 19,024 | 21,376 |
Supplemental information: | |||
Interest paid, net of amounts capitalized | 64,790 | 61,501 | 59,161 |
Income taxes paid (received) | $ (7,854) | $ (31,011) | $ 13,544 |
Consolidated Statements Of Equi
Consolidated Statements Of Equity - USD ($) $ in Thousands | Total | Southwest Gas Corporation [Member] | Common Stock [Member] | Common Stock [Member]Southwest Gas Corporation [Member] | Additional Paid-in Capital [Member] | Additional Paid-in Capital [Member]Southwest Gas Corporation [Member] | Accumulated Other Comprehensive Income (Loss) [Member] | Accumulated Other Comprehensive Income (Loss) [Member]Southwest Gas Corporation [Member] | Retained Earnings [Member] | Retained Earnings [Member]Southwest Gas Corporation [Member] | Non-controlling Interest [Member] | Redeemable Noncontrolling Interest (Temporary Equity) [Member] | ||
Balance at Dec. 31, 2014 | $ 1,486,266 | $ 1,490,121 | $ 48,153 | $ 48,153 | $ 851,381 | $ 851,381 | $ (50,175) | $ (49,538) | $ 639,164 | $ 640,125 | $ (2,257) | $ 20,042 | ||
Balance, Shares at Dec. 31, 2014 | 46,523,000 | 46,523,000 | ||||||||||||
Common stock issuances, Value | 40,144 | 40,144 | $ 854 | $ 854 | 39,290 | 39,290 | ||||||||
Common stock issuances, Shares | 854,000 | 854,000 | ||||||||||||
Net income (loss) | 138,491 | 138,317 | 138,317 | 138,317 | 174 | |||||||||
Net income (loss) attributable to temporary equity | 939 | |||||||||||||
Redemption value adjustments (Note 17) | 4,708 | 5,777 | (1,069) | |||||||||||
Redemption value adjustments attributable to temporary equity | (4,708) | |||||||||||||
Foreign currency exchange translation adj. | (1,888) | (1,888) | ||||||||||||
Foreign currency exchange translation adj attributable to temporary equity | (66) | |||||||||||||
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 6 and 11) | (278) | (278) | (278) | (278) | ||||||||||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,073 | 2,073 | 2,073 | ||||||||||
Centuri distribution to redeemable noncontrolling interest | (99) | |||||||||||||
Dividends declared Common | (77,191) | (77,191) | (77,191) | (77,191) | ||||||||||
Balance at Dec. 31, 2015 | 1,592,325 | 1,593,186 | $ 49,007 | $ 49,007 | 896,448 | 890,671 | (50,268) | (47,743) | 699,221 | 701,251 | (2,083) | |||
Balance, Shares at Dec. 31, 2015 | 47,377,000 | 47,377,000 | ||||||||||||
Balance, Attributable to temporary equity | 16,108 | |||||||||||||
Common stock issuances, Value | 6,780 | 6,780 | $ 105 | $ 105 | 6,675 | 6,675 | ||||||||
Common stock issuances, Shares | 105,000 | 105,000 | ||||||||||||
Net income (loss) | 151,907 | 152,041 | 152,041 | 152,041 | (134) | |||||||||
Net income (loss) attributable to temporary equity | 1,148 | |||||||||||||
Redemption value adjustments (Note 17) | (5,768) | (5,768) | ||||||||||||
Redemption value adjustments attributable to temporary equity | 5,768 | |||||||||||||
Foreign currency exchange translation adj. | 156 | 156 | ||||||||||||
Foreign currency exchange translation adj attributable to temporary equity | 5 | |||||||||||||
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 6 and 11) | 29 | 29 | 29 | 29 | ||||||||||
Amounts reclassified into net income (Notes 6 and 14) | 2,075 | 2,075 | 2,075 | 2,075 | ||||||||||
Centuri distribution to redeemable noncontrolling interest | (439) | |||||||||||||
Dividends declared Common | (86,231) | (86,231) | (86,231) | (86,231) | ||||||||||
Balance at Dec. 31, 2016 | $ 1,661,273 | 1,667,880 | $ 49,112 | $ 49,112 | 903,123 | 897,346 | (48,008) | (45,639) | 759,263 | 767,061 | (2,217) | |||
Balance, Shares at Dec. 31, 2016 | 47,482,068 | 47,482,000 | 47,482,000 | |||||||||||
Balance, Attributable to temporary equity | $ 22,590 | 22,590 | ||||||||||||
Common stock issuances, Value | 52,817 | $ 608 | 52,209 | |||||||||||
Common stock issuances, Shares | 608,000 | |||||||||||||
Net income (loss) | 193,693 | 156,818 | 193,841 | 156,818 | (148) | |||||||||
Net income (loss) attributable to temporary equity | 248 | |||||||||||||
Redemption value adjustments (Note 17) | (355) | (355) | ||||||||||||
Redemption value adjustments attributable to temporary equity | 355 | |||||||||||||
Foreign currency exchange translation adj. | 1,760 | 1,760 | ||||||||||||
Foreign currency exchange translation adj attributable to temporary equity | 11 | |||||||||||||
Redemption of Centuri shares from noncontrolling parties | (23,000) | |||||||||||||
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 6 and 11) | (3,507) | (3,507) | (3,507) | (3,507) | ||||||||||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,073 | 2,073 | 2,073 | ||||||||||
Centuri distribution to redeemable noncontrolling interest | (182,773) | (182,773) | $ (204) | |||||||||||
Stock-based compensation (a) | 9,278 | 10,062 | (784) | |||||||||||
Dividends declared Common | (95,351) | (81,129) | (95,351) | (81,129) | ||||||||||
Contributions from Southwest Gas Holdings, Inc. | 41,359 | 41,359 | ||||||||||||
Balance at Dec. 31, 2017 | $ 1,812,403 | $ 1,609,999 | $ 49,720 | $ 49,112 | $ 955,332 | $ 948,767 | $ (47,682) | $ (47,073) | $ 857,398 | $ 659,193 | $ (2,365) | |||
Balance, Shares at Dec. 31, 2017 | 48,090,470 | 48,090,000 | [1] | 47,482,000 | [1] | |||||||||
[1] | * There are 4.7 million common shares registered and available for issuance under provisions of the various stock issuance plans. In March 2017, the Company registered for issuance common shares with an aggregate sales price of up to $150 million. These shares are not included in the 4.7 million common shares registered and available for issuance. |
Consolidated Statements Of Equ8
Consolidated Statements Of Equity (Parenthetical) - USD ($) shares in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Dividends declared Common, per share | $ 1.98 | $ 1.80 | $ 1.62 |
Shares registered and available for issuance | 4.7 | ||
Common Stock [Member] | |||
Value of common stock | $ 150,000,000 | ||
Southwest Gas Corporation [Member] | |||
Dividends declared Common, per share | $ 1.80 | $ 1.62 |
Summary of Significant Accounti
Summary of Significant Accounting Policies | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Summary of Significant Accounting Policies | Note 1 – Summary of Significant Accounting Policies Nature of Operations. Note 17 – Construction Services Noncontrolling Interests for additional information. In January 2017, a previously contemplated and approved reorganization under a holding company structure was made effective. The reorganization was designed to provide further separation between regulated and unregulated businesses, and to provide additional financing flexibility. Coincident with the effective date of the reorganization, existing shareholders of Southwest Gas Corporation became shareholders of Southwest Gas Holdings, Inc., on a one-for-one Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. Results for the natural gas operations segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures. Centuri is a comprehensive construction services enterprise dedicated to meeting the growing demands of North American utilities, energy and industrial markets. Centuri derives revenue from installation, replacement, repair, and maintenance of energy distribution systems, and developing industrial construction solutions. Centuri operations are generally conducted under the business names of NPL Construction Co. (“NPL”), Canyon Pipeline Construction, Inc. (“Canyon”), NPL Canada Ltd. (“NPL Canada”, formerly Link-Line Contractors Ltd.), W.S. Nicholls Construction, Inc. (“W.S. Nicholls”), and Brigadier Pipelines Inc. (“Brigadier”). Typically, Centuri revenues are lowest during the first quarter of the year due to unfavorable winter weather conditions. Operating revenues typically improve as more favorable weather conditions occur during the summer and fall months. Centuri acquired New England Utility Constructors, Inc. (“Neuco”) in November 2017, thereby expanding its core services in the Northeast region of the United States. See Note 19 – Acquisition of Construction Services Business for more information. Basis of Presentation. Note 18 – Reorganization Impacts – Discontinued Operations Solely Related to Southwest Gas Corporation , and include both current and non-current Prior to the August 2017 purchase of the residual 3.4% interest in Centuri, earnings associated with the 3.4% interest were attributable to the previous noncontrolling parties and therefore, not included in the earnings of the Company. Following the purchase date, 100% of Centuri earnings are attributable to the Company. No substantive change has occurred with regard to the Company’s business segments on the whole as a result of the foregoing organizational changes. Centuri operations continue to be part of continuing operations and included in the consolidated financial statements of Southwest Gas Holdings, Inc. While Centuri has expanded its footprint with the Neuco acquisition, its core business has remained consistent. Southwest Gas Corporation consists of a single segment – natural gas operations. Consolidation. Centuri, through its subsidiaries, holds a 65% interest in a venture to market natural gas engine-driven heating, ventilating, and air conditioning (“HVAC”) technology and products. Centuri consolidates the entity (IntelliChoice Energy, LLC). Centuri, through its subsidiaries, holds a 50% interest in W.S. Nicholls Western Construction LTD. (“Western”), a Canadian construction services company that is a variable interest entity. Centuri determined that it is not the primary beneficiary of the entity due to a shared-power structure; therefore, Centuri does not consolidate the entity and has recorded its investment, and results related thereto, using the equity method. The investment in Western totaled $12.7 million and $10.8 million at December 31, 2017 and 2016, respectively. Both periods include the impacts of foreign currency exchange translation adjustments. No dividends were received from Western during 2017. Dividends of $500,000 were received from Western in 2016. In 2017, a management fee was paid by Western to its partners, including W.S. Nicholls, in accordance with underlying agreements. The equity method investment in Western is included in Other Property and Investments in the Consolidated Balance Sheets of the Company. Centuri’s maximum exposure to loss as a result of its involvement with Western is estimated at $49.3 million. The estimated maximum exposure to loss represents the maximum loss that would be absorbed by Centuri in the event that all of the assets of Western were deemed to be worthless. Centuri recorded earnings of $1.1 million from this investment in 2017, which is included in Other Income (deductions) in the Consolidated Statements of Income. Net Utility Plant. Management determined that utility-related acquisition adjustments were immaterial to both the Company and Southwest as of December 31, 2017 and December 31, 2016, and therefore, combined related amounts with gas plant. Management has, therefore, reclassified the previous year comparative balance sheet presentation to be on the same basis as the most recently completed year-end Other Property and Investments. Southwest Gas Corporation: 2017 2016 Net cash surrender value of COLI policies $ 117,341 $ 106,744 Other property 1,773 1,825 Total Southwest Gas Corporation 119,114 108,569 Centuri property, equipment, and intangibles 554,730 451,114 Centuri accumulated provision for depreciation and amortization (258,906 ) (228,374 ) Other property 13,242 11,034 Total Southwest Gas Holdings, Inc. $ 428,180 $ 342,343 Deferred Purchased Gas Costs. Prepaids and other current assets Income Taxes. Note 13 – Income Taxes regarding recent tax changes enacted, including the remeasurement of deferred tax balances. For regulatory and financial reporting purposes, investment tax credits (“ITC”) related to gas utility operations are deferred and amortized over the life of related fixed assets. As of December 31, 2017, the Company had cumulative earnings of approximately $13 million of book earnings in its foreign jurisdiction. Management previously asserted and continues to assert that all the earnings of Centuri’s Canadian subsidiaries will be permanently reinvested in Canada. As a result, no U.S. deferred income taxes have been recorded related to cumulative foreign earnings. On December 22, 2017, the legislation referred to as the Tax Cuts and Jobs Act (“TCJA”) was enacted. Substantially all of the provisions of the TCJA are effective for taxable years beginning after December 31, 2017. The TCJA includes extensive changes which significantly impact the taxation of business entities, including specific provisions related to regulated public utilities. The more significant changes that impact the Company include the reduction in the corporate federal income tax rate from 35% to 21%, and several technical provisions including, among others, limiting the utilization of net operating losses (“NOLs”) arising after December 31, 2017 to 80% of taxable income, with the ability to indefinitely carryforward unutilized NOLs to reduce future taxable income. For 2017, the Company benefited by the reduction in tax rates related to its construction services segment as a result of the required remeasurement of deferred tax balances based on the reduction in enacted rates, reducing income tax expense in the current year. The regulated operations of Southwest experienced other impacts due to its rate-regulation and the accounting treatment prescribed by U.S. GAAP to reflect the economics of the rate-regulation. Approximately $8 million favorably impacted tax expense for Southwest, while remaining reductions in accumulated deferred income tax balances to reflect the remeasurement were reclassified to regulatory liabilities in Other deferred credits on the balance sheets of Southwest and the Company. See Note 5 – Regulatory Assets and Liabilities and Note 13 – Income Taxes for further information. Cash and Cash Equivalents. Significant non-cash non-cash Adoption of Accounting Standards Update (“ASU”) No. 2016-09. No. 2016-09 Under the new guidance, the Company can withhold any amount between the minimum and maximum individual statutory tax rates and still treat the entire award as equity. The Company intends to administer withholding such that awards under stock compensation programs will continue to be treated as equity awards. In addition to the above, the update requires all income tax-related Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value are required to be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. No previously unrecognized tax benefits existed as a result of these changes; therefore, no cumulative effect adjustment to the opening retained earnings was required. Goodwill. Note 19 – Acquisition of Construction Services Business ) was considered an asset purchase for tax purposes. As a result, goodwill associated with Neuco is expected to be deductible for those same purposes. Southwest Construction Services Total (In thousands of dollars) December 31, 2016 $ 10,095 $ 129,888 $ 139,983 Additional goodwill from New England Utility Constructors, Inc. acquisition — 32,028 32,028 Foreign currency translation adjustment — 7,303 7,303 December 31, 2017 $ 10,095 $ 169,219 $ 179,314 Intangible Assets Non-utility December 31, 2017 Gross Carrying Accumulated Net Carrying Customer relationships $ 76,254 $ (6,743 ) $ 69,511 Trade names and trademarks 13,754 (4,080 ) 9,674 Noncompete agreement 2,060 (543 ) 1,517 Total $ 92,068 $ (11,366 ) $ 80,702 December 31, 2016 Customer relationships $ 34,033 $ (3,906 ) $ 30,127 Trade names and trademarks 9,349 (2,565 ) 6,784 Customer contracts backlog 1,656 (1,656 ) — Noncompete agreement 1,029 (271 ) 758 Total $ 46,067 $ (8,398 ) $ 37,669 The above intangible assets are included in Other property and investments in the Southwest Gas Holdings, Inc. Consolidated Balance Sheets. The estimated future amortization of the intangible assets for the next five years is as follows (in thousands): 2018 $ 6,835 2019 6,240 2020 6,114 2021 5,711 2022 5,626 See Note 2 – Utility Plant and Leases for additional information regarding natural gas operations intangible assets . Note 19 – Acquisition of Construction Services Business includes detailed information about intangible assets purchased in the Neuco acquisition. Accumulated Removal Costs. Gas Operating Revenues. Note 3 – Revenue for additional information regarding natural gas operating revenues. Southwest acts as an agent for state and local taxing authorities in the collection and remission of a variety of taxes, including sales and use taxes and surcharges. These taxes are not included in gas operating revenues. Management uses the net classification method to report taxes collected from customers to be remitted to governmental authorities. Construction Revenues. Note 3 – Revenue for additional information regarding construction revenues. Centuri is required to collect taxes imposed by various governmental agencies on the work performed by Centuri for its customers. These taxes are not included in construction revenues. Management uses the net classification method to report taxes collected from customers to be remitted to governmental authorities. Construction Expenses. job-related Net Cost of Gas Sold. Operations and Maintenance Expense. Depreciation and Amortization. Accumulated Removal Costs Allowance for Funds Used During Construction (“AFUDC”). 2017 2016 2015 (In thousands) AFUDC: Debt portion $ 1,666 $ 1,175 $ 1,666 Equity portion 2,296 2,289 3,008 AFUDC capitalized as part of utility plant $ 3,962 $ 3,464 $ 4,674 AFUDC rate 5.95 % 7.35 % 7.32 % Other Income (Deductions). 2017 2016 2015 Southwest Gas Corporation – natural gas operations segment: Change in COLI policies $ 10,300 $ 7,400 $ (500 ) Interest income 2,784 1,848 1,754 Equity AFUDC 2,296 2,289 3,008 Miscellaneous income and (expense) (2,344 ) (3,261 ) (1,970 ) Southwest Gas Corporation – total other income (deductions) 13,036 8,276 2,292 Construction services segment: Interest income 3 1 419 Foreign transaction gain (loss) (754 ) (22 ) (824 ) Equity in earnings of unconsolidated investment – Western 1,052 69 310 Miscellaneous income and (expense) 44 1,145 682 Centuri – total other income (deductions) 345 1,193 587 Corporate and administrative 13 — — Consolidated Southwest Gas Holdings, Inc. – total other income (deductions) $ 13,394 $ 9,469 $ 2,879 Included in the table above is the change in cash surrender values of company-owned life insurance (“COLI”) policies (including net death benefits recognized). These life insurance policies on members of management and other key employees are used by the Company and Southwest to indemnify against the loss of talent, expertise, and knowledge, as well as to provide indirect funding for certain nonqualified benefit plans. Current tax regulations provide for tax-free Foreign Currency Translation. Earnings Per Share. 2017 2016 2015 (In thousands) Average basic shares 47,965 47,469 46,992 Effect of dilutive securities: Stock options — 1 8 Management Incentive Plan shares 8 124 171 Restricted stock units (1) 18 220 212 Average diluted shares 47,991 47,814 47,383 (1) The number of securities granted for 2017 includes 7,000 performance shares, the total of which was derived by assuming that target performance will be achieved during the relevant performance period. Recently Issued Accounting Standards Updates Note 3 – Revenue . In January 2016, the FASB issued the update “Financial Instruments – Overall (Subtopic 825-10): In February 2016, the FASB issued the update “Leases (Topic 842).” Under the update, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: • A lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and • A right-of-use Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. Though companies have historically been required to make disclosures regarding leases and of associated contractual obligations, leases (with terms longer than a year) will no longer exist off-balance In June 2016, the FASB issued the update “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The update amends guidance on reporting credit losses for financial assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, the update eliminates the “probable” threshold for initial recognition of credit losses in current U.S. GAAP and, instead, requires an entity to reflect its current estimate of all expected credit losses. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net amount expected to be collected. For available for sale debt securities, credit losses should be measured in a manner similar to current U.S. GAAP, however the update will require that credit losses be presented as an allowance rather than as a write-down. This update affects entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The update affects loans, debt securities, trade receivables, net investments in leases, off-balance In August 2016, the FASB issued the update “Classification of Certain Cash Receipts and Cash Payments.” This update addresses the following specific cash flow issues: debt prepayment or debt extinguishment costs; settlement of zero-coupon In October 2016, the FASB issued the update “Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory.” This update eliminates the current U.S. GAAP exception for all intra-entity sales of assets other than inventory. As a result, a reporting entity would recognize the tax expense from the sale of the asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax In January 2017, the FASB issued the update “Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The update eliminates Step 2 from the goodwill impairment test. The annual, or interim, goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. In addition, income tax effects from any tax-deductible In March 2017, the FASB issued the update “Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” The update applies to all employers that offer employee benefits under defined benefit pension plans, other postretirement benefit plans, or other types of benefits accounted for under Topic 715, Compensation – Retirement Benefits. The update requires that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, and be appropriately described. The update also allows only the service cost component (and not the other components of periodic benefit costs) to be eligible for capitalization when applicable, making no exception for specialized industries, including rate-regulated Southwest is a rate-regulated utility offering pension and postretirement benefits to retired employees. It is anticipated that Southwest would continue to request recovery of the total costs of defined benefit plans in rate applications filed with its various regulatory bodies. Rate-regulated entities providing utility and transmission services have historically capitalized a portion of periodic benefit costs (including non-service non-service non-service non-service Subsequent Events. |
Utility Plant and Leases
Utility Plant and Leases | 12 Months Ended |
Dec. 31, 2017 | |
Leases [Abstract] | |
Utility Plant and Leases | Note 2 – Utility Plant and Leases Net utility plant as of December 31, 2017 and 2016 was as follows (thousands of dollars): December 31, 2017 2016 Gas plant: Storage $ 25,019 $ 24,614 Transmission 363,396 349,981 Distribution 5,600,769 5,198,531 General 396,252 382,084 Software and software-related intangibles 230,030 224,260 Other 14,178 14,290 6,629,644 6,193,760 Less: accumulated depreciation (2,231,242 ) (2,172,966 ) Construction work in progress 125,248 111,177 Net utility plant $ 4,523,650 $ 4,131,971 Utility plant depreciation is computed on the straight-line remaining life method at composite rates considered sufficient to amortize costs over estimated service lives, including components which compensate for removal costs (net of salvage value), and retirements, based on the processes of regulatory proceedings and related regulatory commission approvals and/or mandates. In 2017, annual utility depreciation and amortization expense averaged 2.9% of the original cost of depreciable and amortizable property. Average rates in 2016 and 2015 approximated 3.6%. Transmission and Distribution plant (combined), associated with core natural gas delivery infrastructure, constitute the majority of gas plant. Annual utility depreciation expense averaged approximately 3.2% of original cost of depreciable transmission and distribution plant during the period 2015 through 2017. Depreciation and amortization expense on gas plant, including intangibles, was as follows (thousands of dollars): 2017 2016 2015 Depreciation and amortization expense $ 187,075 $ 214,037 $ 201,233 Included in the figures above is amortization of utility intangibles of $14.3 million in 2017, $14.8 million in 2016, and $12.7 million in 2015. Operating Leases and Rentals. 2017 2016 2015 Southwest Gas Corporation $ 4,926 $ 4,357 $ 4,186 Centuri 62,310 53,956 45,849 Consolidated rental payments/lease expense $ 67,236 $ 58,313 $ 50,035 The following is a schedule of future minimum lease payments for operating leases (with initial or remaining terms in excess of one year) as of December 31, 2017 (thousands of dollars): Consolidated Southwest Centuri Total 2018 $ 1,538 $ 7,297 $ 8,835 2019 886 7,188 8,074 2020 714 5,157 5,871 2021 627 3,828 4,455 2022 299 3,364 3,663 Thereafter 116 9,530 9,646 Total minimum lease payments $ 4,180 $ 36,364 $ 40,544 Capital Leases. December 31, 2017 2016 Capital leased assets, gross $ 2,159 $ 3,189 Less: accumulated amortization (1,000 ) (1,172 ) Capital leased assets, net $ 1,159 $ 2,017 The following is a schedule of future minimum lease payments for non-cancelable Year Ending December 31, 2018 $ 709 2019 233 2020 191 2021 — 2022 — Thereafter — 1,133 Less: amount representing interest (84 ) Total minimum lease payments $ 1,049 |
Revenue
Revenue | 12 Months Ended |
Dec. 31, 2017 | |
Revenue from Contract with Customer [Abstract] | |
Revenue | Note 3 – Revenue In May 2014, the FASB issued the update “Revenue from Contracts with Customers (Topic 606).” The update replaces much of the current guidance regarding revenue recognition including most industry-specific guidance. The Company adopted the update on January 1, 2018 using the modified retrospective transition method. Management of both segments of the Company completed assessments of sources of revenue and the effects that adoption of the new guidance will have on the Company’s (and Southwest’s in the case of utility operations) financial position, results of operations, and cash flows. Based on these assessments, such impacts were not material overall. Presentation and disclosure requirements of the new guidance will have the most impact on the financial statements and note disclosures during the first quarter of 2018. The following information about the Company’s revenues is presented by segment. Southwest consists of only one segment – natural gas operations. For more information regarding reportable segments, see Note 15 – Segment Information . Natural Gas Operations Segment: Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest are subject to regulatory oversight. Southwest generally has two types of sales to its customers: tariff sales and transportation–only service. Tariff sales encompass sales to many types of customers (residential customers primarily) under various rate schedules, subject to cost-of-service Similar to tariff sales (which include the provision of the commodity and transportation service), transportation-only service is governed by tariff rate provisions. Transportation-only service is generally only available to very large customers under requirements of Southwest’s various tariffs. With this service, customers secure their own gas supply and Southwest provides transportation services to move the customer commodity to the intended location. Southwest occasionally enters into negotiated rate contracts for customers located in proximity to another pipeline, which, thereby pose a bypass threat. Southwest can also enter into such contracts for potential customers that may be able to otherwise satisfy their energy needs by means of alternative fuel to natural gas. Less than two dozen customers are party to contracts with rate components subject to negotiation. Many rate provisions and terms of service for these less common types of contracts are also subject to regulatory oversight and tariff provisions. Revenues also include the net impacts of margin tracker/decoupling accruals. All of Southwest’s service territories have decoupled rate structures (also referred to as alternative revenue programs) that are designed to eliminate the direct link between volumetric sales and revenue, thereby mitigating the impacts of unusual weather variability and conservation on margin. The primary alternative revenue programs involve permissible adjustments for differences between stated tariff benchmarks and amounts billable through revenue from contracts with customers via existing rates. Such adjustments are currently recognized by entries to revenue and the associated regulatory asset/liability. See Note 5 – Regulatory Assets and Liabilities . Construction Services Segment: Centuri derives revenue from the installation, replacement, repair, and maintenance of energy distribution systems, and in developing industrial construction solutions. Centuri has operations in the U.S. and Canada. The majority of Centuri’s revenues are related to construction contracts for natural gas pipeline replacement and installation work for natural gas utilities. In addition, Centuri performs certain industrial construction activities for various customers and industries. Centuri has two types of agreements with its customers: master services agreements (“MSA”) and bid contracts. Most of Centuri’s customers supply many of their own materials in order for Centuri to complete its work under the contracts An MSA is an agreement that identifies most of the terms describing each party’s rights and obligations that will govern future work authorizations. An MSA is often effective for a period of two to seven years at a time. A work authorization is required to be issued by the customer in order for each party to fully know its rights and obligations. The work authorization will describe the location, timing and any additional information necessary to complete the work for the customer. Each work authorization references the terms and conditions included in the MSA. As such, the combination of the MSA and the work authorization is when a contract exists and revenue recognition may begin. A bid contract is typically a one-time Centuri’s MSA and bid contracts are characterized as either fixed-price contracts or unit-price contracts for revenue recognition purposes. Centuri categorizes work performed under MSAs and bid contracts into three primary service types: replacement gas construction, new gas construction, and other construction. Replacement gas construction includes work involving previously existing gas pipelines requiring replacement for any reason, including due to pipe defect, age or replacement with preferred materials. New gas construction involves the installation of new pipelines or service lines to areas that do not already have gas services. Other construction includes all other work and can include industrial construction, water infrastructure construction, electric infrastructure construction, etc. Actual revenues and project costs can vary, sometimes substantially, from previous estimates due to changes in a variety of factors including unforeseen circumstances not originally contemplated (including at times events not covered by its contracts) preventing it from obtaining adequate compensation. These circumstances can include concealed or unknown environmental conditions; changes in the cost of equipment, commodities, materials or labor; unanticipated costs or claims due to customer-caused delays, customer failure to provide required materials or equipment, errors in engineering, specifications or designs, project modifications, or contract termination and Centuri’s inability to obtain reimbursement for such costs or recover claims; weather conditions; and quality issues requiring rework or replacement. These factors, along with other risks inherent in performing fixed-price contracts may cause actual revenues and gross profit for a project to differ from previous estimates and could result in reduced profitability or losses on projects. Changes in these factors may result in revisions to costs and earnings, the impacts for which are recognized in the period in which the changes are identified; once identified, these types of conditions continue to be evaluated for each project throughout the project term, and ongoing revisions in management’s estimates of contract value, contract cost, and contract profit are recognized as necessary in the period determined. Contracts can have compensation/consideration that is variable. For MSAs, variable consideration is evaluated at the customer level as the terms creating variability in pricing are included within the MSA and are not specific to a work authorization. For multi-year MSAs, the variable consideration items are typically determined for each year of the contract and not for the full contract term. For bid contracts, variable consideration is evaluated at the individual contract level. The expected value method or most likely amount method is used based on the nature of the variable consideration. Types of variable consideration include liquidated damages, delay penalties (payable to or receivable from the customer), performance incentives, safety bonuses, payment discounts, and volume rebates. Centuri will typically estimate variable consideration and adjust financial information as necessary. Change orders involve the modification in scope, price, or both to the current contract, requiring approval by both parties. The existing terms of the contract continue to be accounted until such time as a change order is approved. Once approved, the change order is either treated as a separate contract or as part of the existing contract as appropriate under the circumstances. When the scope is agreed upon in the change order but not the price, Centuri estimates the change to the transaction price. |
Receivables and Related Allowan
Receivables and Related Allowances | 12 Months Ended |
Dec. 31, 2017 | |
Receivables [Abstract] | |
Receivables and Related Allowances | Note 4 – Receivables and Related Allowances Business activity with respect to gas utility operations is conducted with customers located within the three-state region of Arizona, Nevada, and California. The table below contains information about the gas utility customer accounts receivable balance (net of allowance) at December 31, 2017 and 2016, and the percentage of customers in each of the three states. December 31, 2017 December 31, 2016 Gas utility customer accounts receivable balance (in thousands) $ 119,444 $ 111,320 December 31, 2017 Percent of customers by state Arizona 53 % Nevada 37 % California 10 % Although Southwest seeks to minimize its credit risk related to utility operations by requiring security deposits from new customers, imposing late fees, and actively pursuing collection on overdue accounts, some accounts are ultimately not collected. Customer accounts are subject to collection procedures that vary by jurisdiction (late fee assessment, noticing requirements for disconnection of service, and procedures for actual disconnection and/or reestablishment of service). After disconnection of service, accounts are generally written off approximately one month after inactivation. Dependent upon the jurisdiction, reestablishment of service requires both payment of previously unpaid balances and additional deposit requirements. Provisions for uncollectible accounts are recorded monthly based on experience, customer and rate composition, and write-off Allowance for Balance, December 31, 2014 $ 2,255 Additions charged to expense 4,113 Accounts written off, less recoveries (4,098 ) Balance, December 31, 2015 2,270 Additions charged to expense 3,264 Accounts written off, less recoveries (3,010 ) Balance, December 31, 2016 2,524 Additions charged to expense 2,310 Accounts written off, less recoveries (2,723 ) Balance, December 31, 2017 $ 2,111 At December 31, 2017, the construction services segment (Centuri) had $227.6 million in customer accounts receivable. Both the allowance for uncollectibles and write-offs related to Centuri customers have been insignificant and are not reflected in the table above. |
Regulatory Assets and Liabiliti
Regulatory Assets and Liabilities | 12 Months Ended |
Dec. 31, 2017 | |
Regulated Operations [Abstract] | |
Regulatory Assets and Liabilities | Note 5 – Regulatory Assets and Liabilities Southwest is subject to the regulation of the Arizona Corporation Commission (“ACC”), the Public Utilities Commission of Nevada (“PUCN”), the California Public Utilities Commission (“CPUC”), and the Federal Energy Regulatory Commission (“FERC”). Accounting policies of Southwest conform to U.S. GAAP applicable to rate-regulated entities and reflect the effects of the ratemaking process. Accounting treatment for rate-regulated entities allows for deferral as regulatory assets, costs that otherwise would be expensed, if it is probable that future recovery from customers will occur. If rate recovery is no longer probable, due to competition or the actions of regulators, Southwest is required to write-off The following table represents existing regulatory assets and liabilities (thousands of dollars): December 31, 2017 2016 Regulatory assets: Accrued pension and other postretirement benefit costs (1) $ 391,403 $ 379,063 Unrealized net loss on non-trading 5,780 — Deferred purchased gas costs (3) 14,581 2,608 Accrued purchased gas costs (4) 17,000 37,100 Unamortized premium on reacquired debt (5) 20,913 21,975 Accrued absence time (10) 13,870 13,440 Other (6) 68,351 23,557 531,898 477,743 Regulatory liabilities: Deferred purchased gas costs (3) (6,841 ) (90,476 ) Accumulated removal costs (315,000 ) (308,000 ) Unrealized net gain on non-trading — (4,377 ) Unamortized gain on reacquired debt (7) (9,253 ) (9,789 ) Regulatory excess deferred taxes and gross -up (433,908 ) (6,593 ) Other (9) (33,184 ) (18,066 ) Net regulatory assets (liabilities) $ (266,288 ) $ 40,442 (1) Included in Deferred charges and other assets on the Consolidated Balance Sheets. Recovery period is greater than five years. (See Note 11 – Pension and Other Postretirement Benefits (2) The following table details the regulatory assets/(liabilities) offsetting the derivatives (Swaps) at fair value in the Consolidated Balance Sheets (thousands of dollars). The actual amounts, when realized at settlement, become a component of purchased gas costs under Southwest’s purchased gas adjustment (“PGA”) mechanisms. (See Note 14 – Derivatives and Fair Value Measurements Instrument Balance Sheet Location 2017 2016 Swaps Deferred charges and other assets $ 1,323 $ — Swaps Prepaids and other current assets 4,457 — Swaps Other current liabilities — (3,532 ) Swaps Other deferred credits — (845 ) (3) Balance recovered or refunded on an ongoing basis with interest. (4) Included in Prepaids and other current assets on the Consolidated Balance Sheets. Balance recovered or refunded on an ongoing basis. (5) Included in Deferred charges and other assets on the Consolidated Balance Sheets. Recovered over life of debt instruments. (6) The following table details the components of Other regulatory assets which are included in either Prepaids and other current assets or Deferred charges and other assets on the Consolidated Balance Sheets (as indicated). Recovery periods vary. Margin tracking/decoupling mechanisms are alternative revenue programs and revenue associated with under-collections (for the difference between authorized margin levels and amounts billed to customers through rates currently) are recognized as revenue so long as recovery is expected to take place within 24 months. Other Regulatory Assets 2017 2016 State mandated public purpose programs (including low income and conservation programs) (a) (e) $ 4,832 $ 7,096 Margin and interest-tracking accounts (a) (e) 42,354 3,517 Infrastructure replacement programs and similar (b) (e) 9,627 6,976 Environmental compliance programs (c) (e) 9,702 4,329 Other (d) 1,836 1,639 $ 68,351 $ 23,557 a) Included in Prepaids and other current assets on the Consolidated Balance Sheets. See Prepaids and other current assets Note 1 – Summary of Significant Accounting Policies b) Included in Deferred charges and other assets on the Consolidated Balance Sheets. c) 2017 included in Prepaids and other current assets on the Consolidated Balance Sheets ($9.2 million) and Deferred charges and other assets on the Consolidated Balance Sheets ($527,000); 2016 included in Prepaids and other current assets on the Consolidated Balance Sheets ($3.8 million) and Deferred charges and other assets on the Consolidated Balance Sheets ($500,000). d) 2017 included in Prepaids and other current assets on the Consolidated Balance Sheets ($531,000) and Deferred charges and other assets on the Consolidated Balance Sheets ($1.3 million); 2016 included in Prepaids and other current assets on the Consolidated Balance Sheets ($622,000) and Deferred charges and other assets on the Consolidated Balance Sheets ($1 million). e) Balance recovered or refunded on an ongoing basis, generally with interest. (7) Included in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets. Amortized over life of debt instruments. (8) The Tax Cuts and Jobs Act required a remeasurement and reduction of the net deferred income tax liability. The reduction (excess deferred taxes) became a regulatory liability with appropriate tax gross-up. (9) The following table details the components of Other regulatory liabilities which are included in either Other current liabilities or Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets (as indicated). Other Regulatory Liabilities 2017 2016 State mandated public purpose programs (including low income and conservation $ (10,213 ) $ (7,101 ) Margin, interest- and property tax-tracking (9,505 ) (3,668 ) Environmental compliance programs (a) (e) (8,574 ) (4,469 ) Regulatory accounts for differences related to pension funding (c) (3,178 ) (2,284 ) Other (d) (e) (1,714 ) (544 ) $ (33,184 ) $ (18,066 ) a) Included in Other current liabilities on the Consolidated Balance Sheets. b) 2017 included in Other current liabilities ($6.6 million) and Other deferred credits and other long-term liabilities ($2.9 million) on the Consolidated Balance Sheets; 2016 included in Other current liabilities on the Consolidated Balance Sheets. c) Included in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets. d) 2017 included in Other current liabilities on the Consolidated Balance Sheets ($1.7 million) and in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets ($9,000); 2016 included in Other current liabilities on the Consolidated Balance Sheets ($536,000) and in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets ($8,000). e) Balance recovered or refunded on an ongoing basis, generally with interest. (10) Regulatory recovery occurs on a one-year |
Other Comprehensive Income and
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") | 12 Months Ended |
Dec. 31, 2017 | |
Equity [Abstract] | |
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") | Note 6 – Other Comprehensive Income and Accumulated Other Comprehensive Income (“AOCI”) The following information provides insight into amounts impacting Other Comprehensive Income (Loss), both before and after-tax, Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Thousands of dollars) 2017 2016 2015 Before- Tax Net-of- Before- Tax Net-of- Before- Tax Net-of- Defined benefit pension plans: Net actuarial gain/(loss) $ (43,027 ) $ 10,326 $ (32,701 ) $ (22,770 ) $ 8,652 $ (14,118 ) $ (30,519 ) $ 11,597 $ (18,922 ) Amortization of prior service cost 1,335 (507 ) 828 1,335 (507 ) 828 1,335 (507 ) 828 Amortization of net actuarial (gain)/loss 25,445 (9,669 ) 15,776 27,066 (10,285 ) 16,781 34,381 (13,065 ) 21,316 Regulatory adjustment 12,340 250 12,590 (5,584 ) 2,122 (3,462 ) (5,646 ) 2,146 (3,500 ) Pension plans other comprehensive income (loss) (3,907 ) 400 (3,507 ) 47 (18 ) 29 (449 ) 171 (278 ) Forward-starting interest rate swaps (“FSIRS”) (designated hedging activities): Amounts reclassified into net income 3,344 (1,271 ) 2,073 3,345 (1,270 ) 2,075 3,344 (1,271 ) 2,073 FSIRS other comprehensive income (loss) 3,344 (1,271 ) 2,073 3,345 (1,270 ) 2,075 3,344 (1,271 ) 2,073 Total other comprehensive income (loss) – Southwest Gas Corporation (563 ) (871 ) (1,434 ) 3,392 (1,288 ) 2,104 2,895 (1,100 ) 1,795 Foreign currency translation adjustments: Translation adjustments 1,771 — 1,771 161 — 161 (1,954 ) — (1,954 ) Foreign currency other comprehensive income (loss) 1,771 — 1,771 161 — 161 (1,954 ) — (1,954 ) Total other comprehensive income (loss) – Southwest Gas Holdings, Inc. $ 1,208 $ (871 ) $ 337 $ 3,553 $ (1,288 ) $ 2,265 $ 941 $ (1,100 ) $ (159 ) (1) Tax amounts related to existing before-tax before-tax With regard to the table above, and the roll-forward tables below, management recognizes tax impacts (associated with underlying before-tax The estimated amounts that will be amortized from accumulated other comprehensive income or regulatory assets into net periodic benefit cost over the next year are summarized below (in thousands): Retirement plan net actuarial loss $ 32,000 SERP net actuarial loss 1,500 PBOP prior service cost 1,300 Approximately $2.1 million of realized losses (net of tax) related to the FSIRS, included in AOCI at December 31, 2017, will be reclassified into interest expense within the next twelve months as the related interest payments on long-term debt occur. The following table represents a rollforward of AOCI, presented on the Company’s Consolidated Balance Sheets and its Consolidated Statements of Equity: AOCI—Rollforward (Thousands of dollars) Defined Benefit Plans (Note 11) FSIRS (Note 14) Foreign Currency Items Before-Tax Tax After-Tax Before- Tax After-Tax Before- Tax After-Tax AOCI Beginning Balance AOCI December 31, 2016 $ (57,613 ) $ 21,893 $ (35,720 ) $ (15,999 ) $ 6,080 $ (9,919 ) $ (2,369 ) $ — $ (2,369 ) $ (48,008 ) Net actuarial gain/(loss) (43,027 ) 10,326 (32,701 ) — — — — — — (32,701 ) Translation adjustments — — — — — — 1,771 — 1,771 1,771 Other comprehensive income before reclassifications (43,027 ) 10,326 (32,701 ) — — — 1,771 — 1,771 (30,930 ) FSIRS amounts reclassified from AOCI (1) — — — 3,344 (1,271 ) 2,073 — — — 2,073 Amortization of prior service 1,335 (507 ) 828 — — — — — — 828 Amortization of net actuarial loss (2) 25,445 (9,669 ) 15,776 — — — — — — 15,776 Regulatory adjustment (3) 12,340 250 12,590 — — — — — — 12,590 Net current period other (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 1,771 — 1,771 337 Less: Translation adjustment — — — — — — 11 — 11 11 Net current period other (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 1,760 — 1,760 326 Ending Balance AOCI December 31, 2017 $ (61,520 ) $ 22,293 $ (39,227 ) $ (12,655 ) $ 4,809 $ (7,846 ) $ (609 ) $ — $ (609 ) $ (47,682 ) (1) The FSIRS reclassification amounts are included in the Net interest deductions line item on the Consolidated Statements of Income. Tax amounts related to FSIRS balances were estimated using a 38% effective rate. See also discussion above regarding the enactment of the TCJA. (2) These AOCI components are included in the computation of net periodic benefit cost (see Note 11 – Pension and Other Postretirement Benefits (3) The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in the Deferred charges and other assets line item on the Consolidated Balance Sheets). (4) Tax amounts related to existing before-tax before-tax The following table represents a rollforward of AOCI, presented on Southwest’s Consolidated Balance Sheets: AOCI—Rollforward (Thousands of dollars) Defined Benefit Plans (Note 11) FSIRS (Note 14) Before-Tax Tax After- Before- Tax After-Tax AOCI Beginning Balance AOCI December 31, 2016 $ (57,613 ) $ 21,893 $ (35,720 ) $ (15,999 ) $ 6,080 $ (9,919 ) $ (45,639 ) Net actuarial gain/(loss) (43,027 ) 10,326 (32,701 ) — — — (32,701 ) Other comprehensive income before reclassifications (43,027 ) 10,326 (32,701 ) — — — (32,701 ) FSIRS amounts reclassified from AOCI (5) — — — 3,344 (1,271 ) 2,073 2,073 Amortization of prior service cost (6) 1,335 (507 ) 828 — — — 828 Amortization of net actuarial loss (6) 25,445 (9,669 ) 15,776 — — — 15,776 Regulatory adjustment (7) 12,340 250 12,590 — — — 12,590 Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 (1,434 ) Ending Balance AOCI December 31, 2017 $ (61,520 ) $ 22,293 $ (39,227 ) $ (12,655 ) $ 4,809 $ (7,846 ) $ (47,073 ) (5) The FSIRS reclassification amounts are included in the Net interest deductions line item on the Consolidated Statements of Income. Tax amounts related to FSIRS balances were estimated using a 38% effective rate. See also discussion above regarding the enactment of the TCJA. (6) These AOCI components are included in the computation of net periodic benefit cost (see Note 11 – Pension and Other Postretirement Benefits (7) The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in the Deferred charges and other assets line item on the Consolidated Balance Sheets). (8) Tax amounts related to existing before-tax before-tax The following table represents amounts (before income tax impacts) included in Accumulated other comprehensive income (in the table above), that have not yet been recognized in net periodic benefit cost as of December 31, 2017 and 2016: Amounts Recognized in AOCI (Before Tax) (Thousands of dollars) 2017 2016 Net actuarial (loss) gain $ (448,555 ) $ (430,973 ) Prior service cost (4,368 ) (5,703 ) Less: amount recognized in regulatory assets 391,403 379,063 Recognized in AOCI $ (61,520 ) $ (57,613 ) See Note 11 – Pension and Other Postretirement Benefits for more information on the defined benefit pension plans and Note 14 – Derivatives and Fair Value Measurements for more information on the FSIRS. |
Common Stock
Common Stock | 12 Months Ended |
Dec. 31, 2017 | |
Text Block [Abstract] | |
Common Stock | Note 7 – Common Stock In January 2017, the holding company reorganization was made effective and each outstanding share of Southwest Gas Corporation common stock was converted into a share of common stock in Southwest Gas Holdings, Inc., on a one-for-one On March 29, 2017, the Company filed with the Securities and Exchange Commission (“SEC”) an automatic shelf registration statement on Form S-3 No. 333-217018), at-the-market During 2017, the Company issued approximately 103,000 shares of common stock through the Restricted Stock/Unit Plan, and Management Incentive Plan. |
Long-Term Debt
Long-Term Debt | 12 Months Ended |
Dec. 31, 2017 | |
Debt Disclosure [Abstract] | |
Long-Term Debt | Note 8 – Long-Term Debt Carrying amounts of long-term debt and related estimated fair values as of December 31, 2017 and December 31, 2016 are disclosed in the following table. Southwest’s revolving credit facility (including commercial paper) and the variable-rate Industrial Development Revenue Bonds (“IDRBs”) approximate their carrying values, as they are repaid quickly (in the case of credit facility borrowings) and have interest rates that reset frequently. These are categorized as Level 1 due to Southwest’s ability to access similar debt arrangements at measurement dates with comparable terms, including variable/market rates. The fair values of Southwest’s debentures, senior notes, and fixed-rate IDRBs were determined utilizing a market-based valuation approach, where fair values are determined based on evaluated pricing data, such as broker quotes and yields for similar securities adjusted for observable differences. Significant inputs used in the valuation generally include benchmark yield curves, credit ratings and issuer spreads. The external credit rating, coupon rate, and maturity of each security are considered in the valuation, as applicable. The fair values of debentures and fixed-rate IDRBs are categorized as Level 2 (observable market inputs based on market prices of similar securities). The Centuri secured revolving credit and term loan facility and Centuri other debt obligations (not actively traded) are categorized as Level 3, based on significant unobservable inputs to their fair values. Because Centuri’s debt is not publicly traded, fair values for the secured revolving credit and term loan facility and other debt obligations were based on a conventional discounted cash flow methodology and utilized current market pricing yield curves, across Centuri’s debt maturity spectrum, of other industrial bonds with an assumed credit rating comparable to the Company’s. December 31, 2017 December 31, 2016 Carrying Market Carrying Market (Thousands of dollars) Southwest Gas Corporation: Debentures: Notes, 4.45%, due 2020 $ 125,000 $ 129,273 $ 125,000 $ 129,703 Notes, 6.1%, due 2041 125,000 158,304 125,000 149,734 Notes, 3.875%, due 2022 250,000 256,163 250,000 254,900 Notes, 4.875%, due 2043 250,000 283,243 250,000 266,793 Notes, 3.8%, due 2046 300,000 302,970 300,000 283,029 8% Series, due 2026 75,000 96,063 75,000 94,691 Medium-term notes, 7.59% series, due 2017 — — 25,000 25,040 Medium-term notes, 7.78% series, due 2022 25,000 28,714 25,000 29,290 Medium-term notes, 7.92% series, due 2027 25,000 31,542 25,000 31,905 Medium-term notes, 6.76% series, due 2027 7,500 8,882 7,500 8,769 Unamortized discount and debt issuance costs (9,350 ) (9,931 ) 1,173,150 1,197,569 Revolving credit facility and commercial paper 150,000 150,000 5,000 5,000 Industrial development revenue bonds: Variable-rate bonds: Tax-exempt 50,000 50,000 50,000 50,000 2003 Series A, due 2038 50,000 50,000 50,000 50,000 2008 Series A, due 2038 50,000 50,000 50,000 50,000 2009 Series A, due 2039 50,000 50,000 50,000 50,000 Unamortized discount and debt issuance costs (2,119 ) (2,489 ) 197,881 197,511 Less: current maturities — (25,000 ) Long-term debt, less current maturities – Southwest Gas $ 1,521,031 $ 1,375,080 Centuri: Centuri term loan facility 199,578 207,588 $ 106,700 106,819 Unamortized debt issuance costs (1,111 ) (516 ) 198,467 106,184 Centuri secured revolving credit facility 56,472 56,525 41,185 41,292 Centuri other debt obligations 47,952 48,183 52,635 52,840 Less: current maturities (25,346 ) (25,101 ) Long-term debt, less current maturities – Centuri $ 277,545 $ 174,903 Consolidated Southwest Gas Holdings, Inc.: Southwest Gas Corporation long-term debt $ 1,521,031 $ 1,400,080 Centuri long-term debt 302,891 200,004 Less: current maturities (25,346 ) (50,101 ) Long-term debt, less current maturities – Southwest Gas Holdings, Inc. $ 1,798,576 $ 1,549,983 In March 2017, Southwest amended its credit facility, increasing the borrowing capacity from $300 million to $400 million. Also, the facility was previously scheduled to expire in March 2021, but was extended to March 2022. Southwest continues to designate $150 million of capacity related to the facility as long-term debt and has designated the remaining $250 million for working capital purposes. Interest rates for the credit facility are calculated at either the London Interbank Offered Rate (“LIBOR”) or an “alternate base rate,” plus in each case an applicable margin that is determined based on the Southwest’s senior unsecured debt rating. At December 31, 2017, the applicable margin is 1% for loans bearing interest with reference to LIBOR and 0% for loans bearing interest with reference to the alternative base rate. At December 31, 2017, $150 million was outstanding on the long-term portion of the credit facility, $50 million of which was in commercial paper (see commercial paper program discussion below). The effective interest rate on the long-term portion of the credit facility was 2.34% at December 31, 2017. Borrowings under the credit facility ranged from none at various times throughout 2017 to a high of $348 million during the fourth quarter of 2017. With regard to the short-term portion of the credit facility, there were $191 million outstanding at December 31, 2017 and no borrowings outstanding at December 31, 2016. (See Note 9 – Short-Term Debt ). Southwest has a $50 million commercial paper program. Any issuance under the commercial paper program is supported by Southwest’s current revolving credit facility and, therefore, does not represent additional borrowing capacity. Any borrowing under the commercial paper program will be designated as long-term debt. Interest rates for the program are calculated at the then current commercial paper rate. At December 31, 2017, and as noted above, $50 million was outstanding under the commercial paper program. In January 2017, Southwest repaid at maturity the $25 million 7.59% medium-term notes, using available cash on hand. In November 2017, in association with the acquisition of a construction services-related business (refer to Note 19 – Acquisition of Construction Services Business ), Centuri amended and restated its senior secured revolving credit and term loan facility, increasing the borrowing capacity from $300 million to $450 million. The line of credit portion of the facility increased to $250 million; amounts borrowed and repaid under the revolving credit facility are available to be re-borrowed. Interest rates for Centuri’s $450 million secured revolving credit and term loan facility are calculated at LIBOR, the Canadian Dealer Offered Rate (“CDOR”), or an alternate base rate or Canadian base rate, plus in each case an applicable margin that is determined based on Centuri’s consolidated leverage ratio. The applicable margin ranges from 1.00% to 2.25% for loans bearing interest with reference to LIBOR or CDOR and from 0.00% to 1.25% for loans bearing interest with reference to the alternate base rate or Canadian base rate. Centuri is also required to pay a commitment fee on the unfunded portion of the commitments based on their consolidated leverage ratio. The commitment fee ranges from 0.15% to 0.35% per annum. Borrowings under the secured revolving credit facility ranged from a low of $51 million during March 2017 to a high of $104 million during July 2017. At December 31, 2017 $256 million in borrowings were outstanding under the combined secured revolving credit and term loan facility. All amounts outstanding are considered long-term borrowings. The effective interest rate on the secured revolving credit and term loan facility was 3.54% at December 31, 2017. The effective interest rates on Southwest’s variable-rate IDRBs are included in the table below: December 31, 2017 December 31, 2016 2003 Series A 2.44 % 1.47 % 2008 Series A 2.59 % 1.53 % 2009 Series A 2.40 % 1.43 % Tax-exempt 2.56 % 1.51 % In Nevada, interest fluctuations due to changing interest rates on Southwest’s 2003 Series A, 2008 Series A, and 2009 Series A variable-rate IDRBs are tracked and recovered from ratepayers through an interest balancing account. None of the Company’s debt instruments have credit triggers or other clauses that result in default if bond ratings are lowered by rating agencies. Certain debt instruments contain securities ratings covenants that, if set in motion, would increase financing costs. Certain debt instruments also have leverage ratio caps and minimum net worth requirements. At December 31, 2017, the Company is in compliance with all of its covenants. Under the most restrictive of the covenants, approximately $2.1 billion in additional debt could be issued while still meeting the leverage ratio requirement. Relating to the minimum net worth requirement, as of December 31, 2017, there is at least $1 billion of cushion in equity. No specific dividend restrictions exist under the collective covenants. At December 31, 2017, Southwest is in compliance with all of its covenants. Under the most restrictive of the covenants, approximately $2 billion in additional debt could be issued while still meeting the leverage ratio requirement. Relating to the minimum net worth requirement, as of December 31, 2017, there is at least $1 billion of cushion in equity. No specific dividend restrictions exist under the collective covenants. Certain Centuri debt instruments have leverage ratio caps and fixed charge ratio coverage requirements. At December 31, 2017, Centuri is in compliance with all of its covenants. Under the most restrictive of the covenants, Centuri could issue over $69 million in additional debt and meet the leverage ratio requirement. Centuri has at least $28 million of cushion relating to the minimum fixed charge ratio coverage requirement. Centuri’s revolving credit and term loan facility is secured by underlying assets of the construction services segment. Centuri’s covenants limit its ability to provide cash dividends to Southwest Gas Holdings, Inc., its parent. The dividend restriction is equal to a maximum of 50% of its rolling twelve-month consolidated net income. Estimated maturities of long-term debt for the next five years are (in thousands): Southwest Centuri Total 2018 $ — $ 25,346 $ 25,346 2019 — 26,707 26,707 2020 125,000 27,955 152,955 2021 — 25,140 25,140 2022 425,000 194,577 619,577 |
Short-Term Debt
Short-Term Debt | 12 Months Ended |
Dec. 31, 2017 | |
Debt Disclosure [Abstract] | |
Short-Term Debt | Note 9 – Short-Term Debt In March 2017, Southwest Gas Holdings, Inc. entered into a credit facility with a borrowing capacity of $100 million that expires in March 2022. The Company intends to utilize this facility for short-term financing needs. Interest rates for this facility are calculated at either LIBOR or the “alternate base rate,” plus in each case an applicable margin that is determined based on the Company’s senior unsecured debt rating. At December 31, 2017, the applicable margin is 1.125% for loans bearing interest with reference to LIBOR and 0.125% for loans bearing interest with reference to the alternative base rate. The effective interest rate on the credit facility was 3.2% at December 31, 2017. Borrowings under the credit facility ranged from none at various times throughout 2017 to a high of $28.5 million during the third quarter of 2017. At December 31, 2017, $23.5 million was outstanding under this facility. As discussed in Note 8 – Long-Term Debt , Southwest has a $400 million credit facility that is scheduled to expire in March 2022, of which $250 million has been designated by management for working capital purposes. Southwest had $191 million of short-term borrowings outstanding at December 31, 2017 and no short-term borrowings outstanding at December 31, 2016. |
Commitments and Contingencies
Commitments and Contingencies | 12 Months Ended |
Dec. 31, 2017 | |
Commitments and Contingencies Disclosure [Abstract] | |
Commitments and Contingencies | Note 10 – Commitments and Contingencies The Company is a defendant in miscellaneous legal proceedings. The Company is also a party to various regulatory proceedings. The ultimate dispositions of these proceedings are not presently determinable; however, it is the opinion of management that no litigation or regulatory proceeding to which the Company is currently subject will have a material adverse impact on its financial position, results of operations, or cash flows. Southwest maintains liability insurance for various risks associated with the operation of its natural gas pipelines and facilities. In connection with these liability insurance policies, Southwest is responsible for an initial deductible or self-insured retention amount per incident, after which the insurance carriers would be responsible for amounts up to the policy limits. For the policy year August 2017 to July 2018, these liability insurance policies require Southwest to be responsible for the first $1 million (self-insured retention) of each incident plus the first $4 million in aggregate claims above its self-insured retention in the policy year. Through an assessment process, Southwest may determine that certain costs are likely to be incurred in the future related to specific legal matters. In these circumstances and in accordance with accounting policies, Southwest will make an accrual, as necessary. |
Pension and Other Postretiremen
Pension and Other Postretirement Benefits | 12 Months Ended |
Dec. 31, 2017 | |
Retirement Benefits [Abstract] | |
Pension and Other Postretirement Benefits | Note 11 – Pension and Other Postretirement Benefits An Employees’ Investment Plan is offered to eligible employees of Southwest through deduction of a percentage of base compensation, subject to IRS limitations. The Employees’ Investment Plan provides for purchases of various mutual fund investments and Company common stock. One-half 2017 2016 2015 Employee Investment Plan cost $ 5,112 $ 4,976 $ 5,072 Centuri has a separate plan, the cost and liability of which are not significant. A deferred compensation plan is offered to all officers of Southwest and a separate deferred compensation plan for members of the Company’s Board of Directors. The plans provide the opportunity to defer up to 100% of annual cash compensation. One-half A noncontributory qualified retirement plan with defined benefits covering substantially all Southwest employees is available in addition to a separate unfunded supplemental executive retirement plan (“SERP”) which is limited to Southwest’s officers. Postretirement benefits other than pensions (“PBOP”) are provided to qualified retirees for health care, dental, and life insurance benefits. The overfunded or underfunded positions of defined benefit postretirement plans, including pension plans, are recognized in the Consolidated Balance Sheets. Any actuarial gains and losses, prior service costs and transition assets or obligations are recognized in Accumulated other comprehensive income under Stockholders’ equity, net of tax, until they are amortized as a component of net periodic benefit cost. A regulatory asset has been established for the portion of the total amounts otherwise chargeable to accumulated other comprehensive income that are expected to be recovered through rates in future periods. Changes in actuarial gains and losses and prior service costs pertaining to the regulatory asset will be recognized as an adjustment to the regulatory asset account as these amounts are amortized and recognized as components of net periodic pension costs each year. The qualified retirement plan invests the majority of its plan assets in common collective trusts which includes a well-diversified portfolio of domestic and international equity securities and fixed income securities, which are managed by a professional investment manager appointed by Southwest. The investment manager has full discretionary authority to direct the investment of plan assets held in trust within the specific guidelines prescribed by Southwest through the plan’s investment policy statement. In 2016, Southwest adopted a liability driven investment (“LDI”) strategy for part of the portfolio, a form of investing designed to better match the movement in pension plan assets with the impact of interest rate changes and inflation assumption changes on the pension plan liability. The implementation of the LDI strategy will be phased in over time by using a glide path. The glide path is designed to increase the allocation of the plan’s assets to fixed income securities, as the funded status of the plan increases, in order to more closely match the duration of the plan assets to that of the plan liability. Pension plan assets are held in a Master Trust. The pension plan funding policy is in compliance with the federal government’s funding requirements. Pension costs for these plans are affected by the amount and timing of cash contributions to the plans, the return on plan assets, discount rates, and by employee demographics, including age, compensation, and length of service. Changes made to the provisions of the plans may also impact current and future pension costs. Actuarial formulas are used in the determination of pension costs and are affected by actual plan experience and assumptions about future experience. Key actuarial assumptions include the expected return on plan assets, the discount rate used in determining the projected benefit obligation and pension costs, and the assumed rate of increase in employee compensation. Relatively small changes in these assumptions, particularly the discount rate, may significantly affect pension costs and plan obligations for the qualified retirement plan. In determining the discount rate, management matches the plan’s projected cash flows to a spot-rate yield curve based on highly rated corporate bonds. Changes to the discount rate from year-to-year, There was a 75 basis point reduction in the discount rate between years, as reflected below. The methodology utilized to determine the discount rate was consistent with prior years. The weighted-average rate of compensation increase remained the same (consistent with management’s expectations overall). The asset return assumption (which impacts the following year’s expense) remained unchanged. The rates are presented in the table below: December 31, 2017 December 31, 2016 Discount rate 3.75 % 4.50 % Weighted-average rate of compensation increase 3.25 % 3.25 % Asset return assumption 7.00 % 7.00 % Pension expense for 2018 is estimated to be greater than that experienced in 2017. Future years’ expense level movements (up or down) will continue to be greatly influenced by long-term interest rates, asset returns, and funding levels. The following table sets forth the retirement plan, SERP, and PBOP funded statuses and amounts recognized on the Consolidated Balance Sheets and Consolidated Statements of Income. 2017 2016 Qualified SERP PBOP Qualified SERP PBOP (Thousands of dollars) Change in benefit obligations Benefit obligation for service rendered to date at beginning of year (PBO/PBO/APBO) $ 1,048,353 $ 43,311 $ 73,865 $ 1,044,817 $ 42,720 $ 72,632 Service cost 23,392 309 1,468 22,833 331 1,499 Interest cost 46,083 1,883 3,232 46,027 1,859 3,180 Actuarial loss (gain) 133,017 3,334 (71 ) 8,550 1,347 (2,060 ) Benefits paid (47,361 ) (3,110 ) (3,172 ) (73,874 ) (2,946 ) (1,386 ) Benefit obligation at end of year (PBO/PBO/APBO) 1,203,484 45,727 75,322 1,048,353 43,311 73,865 Change in plan assets Market value of plan assets at beginning of year 738,962 — 48,113 736,880 — 43,584 Actual return on plan assets 144,064 — 7,742 39,956 — 4,818 Employer contributions 36,000 3,110 — 36,000 2,946 — Benefits paid (47,361 ) (3,110 ) (1,247 ) (73,874 ) (2,946 ) (289 ) Market value of plan assets at end of year 871,665 — 54,608 738,962 — 48,113 Funded status at year end $ (331,819 ) $ (45,727 ) $ (20,714 ) $ (309,391 ) $ (43,311 ) $ (25,752 ) Weighted-average assumptions (benefit obligation) Discount rate 3.75 % 3.75 % 3.75 % 4.50 % 4.50 % 4.50 % Weighted-average rate of compensation increase 3.25 % 3.25 % N/A 3.25 % 3.25 % N/A Estimated funding for the plans above during calendar year 2018 is approximately $47 million, of which $44 million pertains to the retirement plan. Management monitors plan assets and liabilities and could, at its discretion, increase plan funding levels above the minimum in order to achieve a desired funded status and avoid or minimize potential benefit restrictions. The accumulated benefit obligation for the retirement plan and the SERP is presented below (in thousands): December 31, 2017 December 31, 2016 Retirement plan $ 1,088,203 $ 939,002 SERP 44,343 40,852 Benefits expected to be paid for pension, SERP, and PBOP over the next 10 years are as follows (in millions): 2018 2019 2020 2021 2022 2023-2027 Pension $ 51.0 $ 52.2 $ 53.6 $ 55.1 $ 56.6 $ 308.3 SERP 3.0 3.0 3.0 2.9 2.9 14.1 PBOP 4.1 4.2 4.3 4.3 4.2 19.6 No assurance can be made that actual funding and benefits paid will match these estimates. For PBOP measurement purposes, the per capita cost of the covered health care benefits medical rate trend assumption is 6.5% declining to 4.5%. Fixed contributions are made for health care benefits of employees who retire after 1988, but Southwest pays all covered health care costs for employees who retired prior to 1989. The medical trend rate assumption noted above applies to the benefit obligations of pre-1989 Components of net periodic benefit cost Qualified Retirement Plan SERP PBOP 2017 2016 2015 2017 2016 2015 2017 2016 2015 (Thousands of dollars) Service cost $ 23,392 $ 22,833 $ 25,123 $ 309 $ 331 $ 320 $ 1,468 $ 1,499 $ 1,641 Interest cost 46,083 46,027 44,229 1,883 1,859 1,695 3,232 3,180 2,999 Expected return on plan assets (55,196 ) (56,558 ) (57,808 ) — — — (3,358 ) (3,149 ) (3,464 ) Amortization of prior service cost — — — — — — 1,335 1,335 1,335 Amortization of net actuarial loss 24,004 25,266 32,743 1,441 1,383 1,293 — 417 345 Net periodic benefit cost $ 38,283 $ 37,568 $ 44,287 $ 3,633 $ 3,573 $ 3,308 $ 2,677 $ 3,282 $ 2,856 Weighted-average Discount rate 4.50 % 4.50 % 4.25 % 4.50 % 4.50 % 4.25 % 4.50 % 4.50 % 4.25 % Expected return on plan assets 7.00 % 7.25 % 7.75 % N/A N/A N/A 7.00 % 7.25 % 7.75 % Weighted-average rate of compensation increase 3.25 % 3.25 % 2.75 % 3.25 % 3.25 % 2.75 % N/A N/A N/A Other Changes in Plan Assets and Benefit Obligations Recognized in Net Periodic Benefit Cost and Other Comprehensive Income 2017 2016 2015 Total Qualified SERP PBOP Total Qualified SERP PBOP Total Qualified SERP PBOP (Thousands of dollars) Net actuarial loss (gain) (a) $ 43,027 $ 44,149 $ 3,334 $ (4,456 ) $ 22,770 $ 25,153 $ 1,347 $ (3,730 ) $ 30,519 $ 26,949 $ 2,322 $ 1,248 Amortization of prior (1,335 ) — — (1,335 ) (1,335 ) — — (1,335 ) (1,335 ) — — (1,335 ) Amortization of net (25,445 ) (24,004 ) (1,441 ) — (27,066 ) (25,266 ) (1,383 ) (417 ) (34,381 ) (32,743 ) (1,293 ) (345 ) Regulatory adjustment (12,340 ) (18,131 ) — 5,791 5,584 102 — 5,482 5,646 5,214 — 432 Recognized in other comprehensive (income) loss 3,907 2,014 1,893 — (47 ) (11 ) (36 ) — 449 (580 ) 1,029 — Net periodic benefit costs recognized in net income 44,593 38,283 3,633 2,677 44,423 37,568 3,573 3,282 50,451 44,287 3,308 2,856 Total of amount $ 48,500 $ 40,297 $ 5,526 $ 2,677 $ 44,376 $ 37,557 $ 3,537 $ 3,282 $ 50,900 $ 43,707 $ 4,337 $ 2,856 The table above discloses the net gain or loss and prior service cost recognized in other comprehensive income, separated into (a) amounts initially recognized in other comprehensive income, and (b) amounts subsequently recognized as adjustments to other comprehensive income as those amounts are amortized as components of net periodic benefit cost. See also Note 6 – Other Comprehensive Income and Accumulated Other Comprehensive Income (“AOCI”) . U.S. GAAP states that a fair value measurement should be based on the assumptions that market participants would use in pricing the asset or liability and establishes a fair value hierarchy that ranks the inputs used to measure fair value by their reliability. The three levels of the fair value hierarchy are as follows: Level 1 – quoted prices (unadjusted) in active markets for identical assets or liabilities that a company has the ability to access at the measurement date. Level 2 – inputs other than quoted prices included within Level 1 that are observable for similar assets or liabilities, either directly or indirectly. Level 3 – unobservable inputs for the asset or liability. Unobservable inputs are used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. The following table sets forth, by level within the three-level fair value hierarchy, the fair values of the assets of the qualified pension plan and the PBOP as of December 31, 2017 and December 31, 2016. The SERP has no assets. December 31, 2017 December 31, 2016 Qualified PBOP Total Qualified PBOP Total Assets at fair value (thousands of dollars): Level 1 – Quoted prices in active markets for identical financial assets Mutual funds $ — $ 27,020 $ 27,020 $ — $ 24,922 $ 24,922 Total Level 1 Assets (1) $ — $ 27,020 $ 27,020 $ — $ 24,922 $ 24,922 Level 2 – Significant other observable inputs Private commingled equity funds (2) International $ 340,217 $ 10,577 $ 350,794 $ 290,668 $ 9,140 $ 299,808 Large and medium capitalization 136,982 4,258 141,240 121,434 3,819 125,253 Small capitalization 28,955 900 29,855 25,947 816 26,763 Emerging markets 56,259 1,749 58,008 45,309 1,424 46,733 Private commingled fixed income funds (3) U.S. corporate bonds 157,460 4,895 162,355 161,086 5,066 166,152 U.S. debt market long duration 59,986 1,865 61,851 77,349 2,432 79,781 U.S. Treasury securities 83,771 2,604 86,375 8,665 272 8,937 Pooled funds and mutual funds 4,676 735 5,411 4,889 216 5,105 Government fixed income and mortgage backed securities 172 5 177 167 5 172 Total Level 2 assets (4) $ 868,478 $ 27,588 $ 896,066 $ 735,514 $ 23,190 $ 758,704 Total Plan assets at fair value $ 868,478 $ 54,608 $ 923,086 $ 735,514 $ 48,112 $ 783,626 Insurance company general account contracts (5) 3,187 — 3,187 3,448 — 3,448 Total Plan assets $ 871,665 $ 54,608 $ 926,273 $ 738,962 $ 48,112 $ 787,074 (1) The Mutual funds category above is an intermediate-term bond fund whose manager employs multiple concurrent strategies and takes only moderate risk in each, thereby reducing the risk of poor performance arising from any single source, and a balanced fund that invests in a diversified portfolio of common stocks, preferred stocks and fixed-income securities. Strategies utilized by the bond fund include duration management, yield curve or maturity structuring, sector rotation, and all bottom-up in-house (2) The private commingled equity funds include common collective trusts that invest in a diversified portfolio of domestic and international securities regularly traded on securities exchanges. These funds are shown in the above table at net asset value (“NAV”), which is the value of securities in the fund less the amount of any liabilities outstanding. Investment strategies employed by the funds include: • Domestic equities • International developed countries equities • Emerging markets equities Shares in the private equity commingled funds may be redeemed given one business day notice. While they are private equity funds and reported at NAV, due to the short redemption notice period, the lack of significant redemption fees, the fact that the underlying investments are exchange-traded, and that substantial liabilities do not exist subject to the NAV calculation, these investments are viewed as indirectly observable (level 2) and are also therefore, not excluded from the body of the fair value table as a reconciling item. Two funds are classified as international funds. One invests in international financial markets, primarily those of developed economies in Europe and the Pacific Basin. The fund invests primarily in equity securities issued by foreign corporations, but may invest in other securities perceived as offering attractive investment return opportunities. The other provides diversified exposure to global equity markets. The fund seeks to provide long-term capital growth by investing primarily in securities listed on the major developed equity markets of the United States, Europe, and Asia, as well as within those listed on emerging country equity markets on a tactical basis. The large and medium capitalization fund is designed to track the performance of the large and medium capitalization companies contained in the index, which represents approximately 90% of the market capitalization of the United States stock market. The small capitalization fund is designed to provide maximum long-term appreciation through investments that are well diversified by industry. The emerging markets fund was developed to invest in emerging market equities worldwide. The purposes of the fund’s operations, “emerging market countries” include every country in the world except the developed markets of the United States, Canada, Japan, Australia, New Zealand, Hong Kong and Singapore, and most countries located in Western Europe. Fund investments are made directly in each country or, where direct investment is inefficient or prohibited, through appropriate financial instruments or participation in commingled funds. (3) The private commingled fixed income funds include domestic fixed income securities. These funds are shown in the above table at NAV. Shares in the private commingled fixed equity funds may be redeemed given one business day notice. While they are private equity funds and reported at NAV, due to the short redemption notice period, the lack of significant redemption fees, the fact that the underlying investments are exchange-traded, and that substantial liabilities do not exist subject to the NAV calculation, these investments are viewed as indirectly observable (level 2) and are also therefore, not excluded from the body of the fair value table as a reconciling item. The U.S. corporate bond fund seeks to provide high quality, mostly corporate bond-based exposure to fixed income securities which closely match those found in discount curves used to value United States pension liabilities. The United States debt market long duration fund provides participation in the full spectrum of investment opportunities in primarily United States debt markets with longer maturities. The fund seeks to offer effective diversification against equities, take advantage of market trading opportunities, and provide a competitive rate of return on assets. The fund’s current duration is close to 14 years. The United States Treasuries securities fund seeks to replicate the risk and return characteristics of the Barclays Treasury U.S. Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) 28-29 (4) With the exception of items (2) and (3), which are discussed in detail above, the Level 2 assets consist mainly of pooled funds and mutual funds. These funds are collective short-term funds that invest in Treasury bills and money market funds and are used as a temporary cash repository. (5) The insurance company general account contracts are annuity insurance contracts used to pay the pensions of employees who retired prior to 1989. The balance of the account disclosed in the above table is the contract value, which is the result of deposits, withdrawals, and interest credits. |
Stock-Based Compensation
Stock-Based Compensation | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Stock-Based Compensation | Note 12 – Stock-Based Compensation At December 31, 2017, three stock-based compensation plans existed at Southwest: an omnibus incentive plan, a management incentive plan, and a restricted stock/unit plan. All previous grants under the stock option plan expired in 2016. The table below shows total stock-based plan compensation expense, including the cash award, which was recognized in the Consolidated Statements of Income (in thousands): 2017 2016 2015 Stock-based compensation plan expense, net of related tax benefits $ 6,751 $ 7,185 $ 7,278 Stock-based compensation plan related tax benefits 4,137 4,404 4,461 Under the option plan, options to purchase shares of common stock at a stated exercise price were previously granted to key employees and outside directors. The last option grants were in 2006 and no future grants are currently anticipated. Each option had an exercise price equal to the market price of the Company’s common stock on the date of grant and a maximum term of ten years. The final options were exercised in 2016. The following tables summarize the stock option plan activity and related information (thousands of options): 2017 2016 2015 Number Weighted- Number of Weighted- Number of Weighted- Outstanding at the beginning of the year — N/A 17 $ 31.64 36 $ 28.97 Exercised during the year — — (17 ) 31.64 (19 ) 26.69 Forfeited or expired during the year — — — — — — Outstanding and exercisable at year end — N/A — N/A 17 $ 31.64 The intrinsic value of a stock option is the amount by which the market value of the underlying stock exceeds the exercise price of the option. The aggregate intrinsic value of outstanding and exercisable options, and options that were exercised, are presented in the table below (in thousands): 2017 2016 2015 Outstanding and exercisable $ — $ — $ 394 Exercised — 554 590 December 31, 2017 December 31, 2016 December 31, 2015 Market value of Company stock $ 80.48 $ 76.62 $ 55.16 In 2017, the Board of Directors of the Company and shareholders approved the omnibus incentive plan. The purpose of the omnibus incentive plan is to promote the long-term growth and profitability of the Company by providing directors, employees and certain other individuals with incentives to increase shareholder value and otherwise contribute to the success of the Company. In addition, the plan will enable the Company to attract, retain, and reward the best available persons for positions of responsibility. Annual grants are expected to be made under the omnibus incentive plan for the first time in February 2018. The omnibus incentive plan provides for the grant of stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, and other equity-based and cash awards. Employees, directors and consultants who provide services to the Company or any subsidiary may be eligible under this plan. One million shares are available for issuance under the omnibus incentive plan. Under the management incentive plan, shares were issued to encourage key employees of Southwest to remain as employees and to achieve short-term and long-term performance goals. Plan participants were eligible to receive a cash bonus (i.e., short-term incentive) and shares (i.e., long-term incentive). The shares vest three years after grant and are then issued as common stock. No new grants will be made under the management incentive plan as all future incentive compensation will be granted under the omnibus incentive plan. Restricted stock/units under the restricted stock/unit plan were issued to attract, motivate, retain, and reward key employees of Southwest with an incentive to attain high levels of individual performance and improved financial performance. The restricted stock/units vest 40% at the end of year one and 30% at the end of years two and three and are issued annually as common stock in accordance with the percentage vested. The restricted stock/unit plan was also established to attract, motivate, and retain experienced and knowledgeable independent directors. Vesting for grants of restricted stock/units to directors occurred immediately upon grant. The issuance of common stock for directors currently occurs when their service on the Board ends. No new grants will be made under the restricted stock/unit plan as all future incentive compensation will be granted under programs of the omnibus incentive plan. Performance-based incentive opportunities under the restricted stock/unit plan were granted to all officers of Southwest in the form of performance shares and will be based on, depending on the officer, consolidated earnings per share, utility net income, and utility return on equity, with an adjustment based on relative total shareholder return, in each case, measured over a three-year performance period from January 1, 2017 to December 31, 2019. During 2017, Southwest recorded $1.2 million of estimated compensation expense associated with these shares. The following table summarizes the activity of the management incentive plan shares and restricted stock/units as of December 31, 2017 (thousands of shares): Management Weighted- Restricted Weighted- Nonvested/unissued at beginning of year 168 $ 55.62 262 $ 46.41 Granted 32 85.44 106 85.39 Dividends 3 7 Forfeited or expired (1 ) 59.02 (1 ) 69.85 Vested and issued (2) (75 ) 51.93 (69 ) 53.28 Nonvested/unissued at December 31, 2017 127 $ 63.98 305 $ 57.41 (1) The number of securities granted includes 33,000 performance shares, which was derived by assuming that target performance will be achieved during the relevant performance period. (2) Includes shares for retiree payouts and those converted for taxes. The weighted average grant date fair value of management incentive plan shares granted in 2016 and 2015 was $59.05 and $63.09, respectively. The weighted average grant date fair value of restricted stock/units granted in 2016 and 2015 was $60.39 and $63.09, respectively. As of December 31, 2017, total compensation cost related to nonvested management incentive plan shares and restricted stock/units not yet recognized is $4.4 million. |
Income Taxes
Income Taxes | 12 Months Ended |
Dec. 31, 2017 | |
Income Tax Disclosure [Abstract] | |
Income Taxes | Note 13 – Income Taxes On December 22, 2017, legislation referred to as the “Tax Cuts and Jobs Act” (the “TCJA”) was enacted. The majority of the provisions of the TCJA are effective for taxable years beginning after December 31, 2017. The TCJA significantly changes the taxation of business entities with specific provisions for regulated public utilities, such as Southwest. The following are the major provisions (not all-inclusive) (1) Reduction of the federal income tax rate from 35% to 21% effective January 1, 2018. (2) Bonus depreciation considerations for utility property placed-in-service (3) 100% bonus depreciation for most non-utility placed-in-service (4) Interest expense limitations for interest allocable to non-utility Changes from the TCJA had a material impact on the Company’s financial statements in 2017. Under U.S. GAAP, specifically Accounting Standards Codification Topic 740 Income Taxes (“ASC 740”), the tax effects of changes in tax laws must be recognized in the period in which the law is enacted. Therefore, the TCJA impacted the Company’s financial statements in the quarter ended December 31, 2017. ASC 740 also requires deferred tax assets and liabilities to be re-measured re-measured The staff of the SEC recognized the complexity of determining the impact of the TCJA, and on December 22, 2017 issued guidance in Staff Accounting Bulletin 118 (“SAB 118”). SAB 118 provides that to the extent the accounting for certain income tax effects of the TCJA is incomplete, but a company can determine a reasonable estimate for those effects, the company may include in its financial statements the reasonable estimate that it had determined. The reasonable estimate would be reported as a provisional amount in the company’s financial statements during a “measurement period”, not to exceed one year from the date of enactment of the TCJA. Southwest and the Company have included provisional reasonable estimates for the measurement and accounting of the effects of the TCJA, which have been reflected in the financial statements as of December 31, 2017 and for the period then ended. The Company and Southwest will continue to analyze and refine the estimates and classification of all provisional items, during the measurement period, as additional accounting, regulatory, and U.S. Treasury guidance is provided. Southwest Gas Holdings, Inc. The following is a summary of income before taxes and noncontrolling interest for domestic and foreign operations (thousands of dollars): Year ended December 31, 2017 2016 2015 U.S. $ 246,131 $ 218,810 $ 221,660 Foreign 12,899 12,713 (2,328 ) Total income before income taxes $ 259,030 $ 231,523 $ 219,332 Income tax expense (benefit) consists of the following (thousands of dollars): Year Ended December 31, 2017 2016 2015 Current: Federal $ (1,316 ) $ 541 $ 21,321 State 2,965 5,748 9,899 Foreign 5,203 4,298 650 6,852 10,587 31,870 Deferred: Federal 58,443 68,270 51,132 State 1,837 140 (2,574 ) Foreign (2,044 ) (529 ) (526 ) 58,236 67,881 48,032 Total income tax expense $ 65,088 $ 78,468 $ 79,902 Deferred income tax expense (benefit) consists of the following significant components (thousands of dollars): Year Ended December 31, 2017 2016 2015 Deferred federal and state: Property-related items $ 44,516 $ 76,217 $ 65,931 Purchased gas cost adjustments 8,500 361 (32,993 ) Employee benefits (2,517 ) (1,327 ) 623 Regulatory Adjustments 14,401 6,322 1,545 All other deferred (5,935 ) (12,854 ) 13,787 Total deferred federal and state 58,965 68,719 48,893 Deferred ITC, net (729 ) (838 ) (861 ) Total deferred income tax expense $ 58,236 $ 67,881 $ 48,032 A reconciliation of the U.S. federal statutory rate to the consolidated effective tax rate for 2017, 2016, and 2015 (and the sources of these differences and the effect of each) are summarized as follows: Year Ended December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.0 % 35.0 % 35.0 % Net state taxes 1.1 1.4 1.8 Property-related items — — 0.1 Tax credits (0.4 ) (0.4 ) (0.4 ) Company owned life insurance (1.6 ) (1.2 ) 0.1 Change in U.S. Federal Income Tax Rate (7.8 ) — — All other differences (1.2 ) (0.9 ) (0.2 ) Consolidated effective income tax rate 25.1 % 33.9 % 36.4 % Deferred tax assets and liabilities consist of the following (thousands of dollars): December 31, 2017 2016 Deferred tax assets: Deferred income taxes for future amortization of ITC and excess deferred taxes $ 98,912 $ 1,094 Employee benefits 31,323 38,231 Alternative minimum tax credit 4,390 4,827 Net operating losses and credits 11,460 1,204 Interest rate swap 3,037 6,080 Other 13,870 18,415 Valuation allowance (728 ) (495 ) 162,264 69,356 Deferred tax liabilities: Property-related items, including accelerated depreciation 598,371 872,136 Regulatory balancing accounts 6,067 1,104 Unamortized ITC 981 1,710 Debt-related costs 3,380 5,712 Intangibles 7,656 8,803 Other 21,289 19,256 637,744 908,721 Net noncurrent deferred tax liabilities $ 475,480 $ 839,365 A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (thousands of dollars): 2017 2016 Unrecognized tax benefits at beginning of year $ 1,231 $ 296 Gross increases – tax positions in prior period 100 897 Gross decreases – tax positions in prior period — — Gross increases – current period tax positions 99 38 Gross decreases – current period tax positions — — Settlements — — Lapse in statute of limitations — — Unrecognized tax benefits at end of year $ 1,430 $ 1,231 Southwest Gas Corporation The following is a summary of income before taxes for continuing and discontinued operations (refer to Note 1 – Summary of Significant Accounting Policies ) (thousands of dollars): Year ended December 31, 2017 2016 2015 Income from continuing operations before income taxes $ 219,953 $ 178,007 $ 172,980 Income from discontinued operations before income taxes — 53,516 46,352 Total income before income taxes $ 219,953 $ 231,523 $ 219,332 Income tax expense (benefit) consists of the following (thousands of dollars): Year Ended December 31, 2017 2016 2015 Current: Federal $ 318 $ (9,695 ) $ 3,789 State 1,420 2,510 6,229 1,738 (7,185 ) 10,018 Deferred: Federal 60,662 66,037 53,657 State 735 (268 ) (2,320 ) 61,397 65,769 51,337 Total income tax expense from continuing operations 63,135 58,584 61,355 Discontinued operations — 19,884 18,547 Total income tax expense $ 63,135 $ 78,468 $ 79,902 Deferred income tax expense (benefit) consists of the following significant components (thousands of dollars): Year Ended December 31, 2017 2016 2015 Deferred federal and state: Property-related items $ 49,129 $ 72,811 $ 68,105 Purchased gas cost adjustments 8,500 361 (32,993 ) Employee benefits (5,707 ) (139 ) (4,795 ) Regulatory Adjustments 14,401 6,322 1,545 All other deferred (4,197 ) (12,748 ) 20,336 Total deferred federal and state 62,126 66,607 52,198 Deferred ITC, net (729 ) (838 ) (861 ) Total deferred income tax expense $ 61,397 $ 65,769 $ 51,337 A reconciliation of the U.S. federal statutory rate to the consolidated effective tax rate for 2017, 2016, and 2015 (and the sources of these differences and the effect of each) are summarized as follows: Year Ended December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.0 % 35.0 % 35.0 % Net state taxes 0.6 0.8 1.0 Property-related items — — 0.1 Tax credits (0.4 ) (0.5 ) (0.5 ) Company owned life insurance (1.7 ) (1.5 ) — Change in U.S. Federal Income Tax Rate (3.6 ) — — All other differences (1.2 ) (0.9 ) (0.1 ) Effective income tax rate from continuing operations 28.7 % 32.9 % 35.5 % Deferred tax assets and liabilities consist of the following (thousands of dollars): December 31, 2017 2016 Deferred tax assets: Deferred income taxes for future amortization of ITC and excess deferred taxes $ 98,912 $ 1,094 Employee benefits 18,707 22,426 Alternative minimum tax credit 4,390 4,827 Net operating losses and credits 10,070 — Interest rate swap 3,037 6,080 Other 8,820 15,204 Valuation allowance (58 ) (223 ) 143,878 49,408 Deferred tax liabilities: Property-related items, including accelerated depreciation 561,493 830,758 Regulatory balancing accounts 6,067 1,104 Unamortized ITC 981 1,710 Debt-related costs 3,380 5,712 Other 17,200 16,233 589,121 855,517 Net deferred tax liabilities before discontinued operations 445,243 806,109 Discontinued operations — 33,256 Net deferred tax liabilities $ 445,243 $ 839,365 A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (thousands of dollars): 2017 2016 Unrecognized tax benefits at beginning of year $ 903 $ — Gross increases – tax positions in prior period 67 865 Gross decreases – tax positions in prior period — — Gross increases – current period tax positions 99 38 Gross decreases – current period tax positions — — Settlements — — Lapse in statute of limitations — — Unrecognized tax benefits at end of year $ 1,069 $ 903 The Company’s regulated operations accounting for income taxes is impacted by the FASB’s ASC 980 – Regulated Operations. Reductions in accumulated deferred income tax balances due to the reduction in the corporate income tax rates to 21% under the provisions of the TCJA may result in a refund of excess deferred taxes to customers, generally through reductions in future rates. The TCJA includes provisions that stipulate how these excess deferred taxes are to be passed back to customers for certain accelerated tax depreciation benefits. Potential refunds of other deferred taxes will be determined in conjunction with appropriate regulatory commissions. The December 31, 2017 balance sheets of Southwest and the Company reflect the impact of the TCJA on regulatory asset and liability balances. Deferred tax liabilities were reduced by $450 million with an increase in regulatory liabilities of $430 million. These adjustments had no impact on 2017 cash flows. The Company and its subsidiaries file a consolidated federal income tax return in the United States and in various states, as well as in Canada. With few exceptions, the Company is no longer subject to United States federal, state and local, or Canadian income tax examinations for years before 2013. The Company and each of its subsidiaries, including Southwest, participate in a tax sharing agreement to establish the method for allocating tax benefits and losses among members of the consolidated group. The consolidated federal income tax is apportioned among the subsidiaries using a separate return method. At December 31, 2017, the Company has a federal net operating loss carryforward of $54.6 million which begins to expire in 2038. The Company also has general business credits of $329,000, which begin to expire in 2038. The Company has net capital loss carryforwards of $278,000, which begin to expire in 2018. At December 31, 2017, the Company has an income tax net operating loss carryforward related to Canadian operations of $5.2 million, which begins to expire in 2032. Management intends to continue to permanently reinvest any future foreign earnings in Canada. In assessing whether uncertain tax positions should be recognized in its financial statements, management first determines whether it is more-likely-than-not more-likely-than-not more-likely-than-not more-likely-than-not At December 31, 2017, the total amount of unrecognized tax benefits that, if recognized, would impact the effective tax rate was $1.1 million individually for both the Company and Southwest. No significant increases or decreases in unrecognized tax benefit are expected within the next 12 months. The Company and Southwest recognize interest expense and income and penalties related to income tax matters in income tax expense. There was no tax-related |
Derivatives and Fair Value Meas
Derivatives and Fair Value Measurements | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Derivatives and Fair Value Measurements | Note 14 – Derivatives and Fair Value Measurements Derivatives. fixed-for-floating The fixed-price contracts and Swaps are utilized by Southwest under its volatility mitigation programs to effectively fix the price on a portion (up to 25% in the Arizona and California jurisdictions) of its natural gas supply portfolios. The maturities of the Swaps highly correlate to forecasted purchases of natural gas, during time frames ranging from January 2018 through October 2019. Under such contracts, Southwest pays the counterparty a fixed rate and receives from the counterparty a floating rate per MMBtu (“dekatherm”) of natural gas. Only the net differential is actually paid or received. The differential is calculated based on the notional amounts under the contracts, which are detailed in the table below (thousands of dekatherms): December 31, 2017 December 31, 2016 Contract notional amounts 10,929 10,543 Southwest does not utilize derivative financial instruments for speculative purposes, nor does it have trading operations. The following table sets forth the gains and (losses) recognized on Southwest’s Swaps (derivatives) for the years ended December 31, 2017, 2016, and 2015 and their location in the Consolidated Statements of Income: Instrument Location of Gain or (Loss) 2017 2016 2015 Swaps Net cost of gas sold $ (11,572 ) $ 5,006 $ (7,598 ) Swaps Net cost of gas sold 11,572 * (5,006 )* 7,598 * Total $ — $ — $ — * Represents the impact of regulatory deferral accounting treatment under U.S. GAAP for rate-regulated entities. No gains (losses) were recognized in net income or other comprehensive income during the periods presented for derivatives designated as cash flow hedging instruments. Previously, Southwest entered into two forward-starting interest rate swaps (“FSIRS”), both of which were designated cash flow hedges, to partially hedge the risk of interest rate variability during the period leading up to the planned issuance of debt. The first FSIRS terminated in December 2010, and the second, in March 2012. Losses on both FSIRS are being amortized over ten-year The following table sets forth the fair values of the Swaps and their location in the Consolidated Balance Sheets of Southwest and the Company (thousands of dollars): Fair values of derivatives not designated as hedging instruments: December 31, 2017 Instrument Balance Sheet Location Asset Liability Net Swaps Other current liabilities $ 11 $ (4,468 ) $ (4,457 ) Swaps Other deferred credits 19 (1,342 ) (1,323 ) Total $ 30 $ (5,810 ) $ (5,780 ) December 31, 2016 Balance Sheet Location Asset Liability Net Swaps Deferred charges and other assets $ 899 $ (54 ) $ 845 Swaps Prepaids and other current assets 3,551 (19 ) 3,532 Total $ 4,450 $ (73 ) $ 4,377 The estimated fair values of the natural gas derivatives were determined using future natural gas index prices (as more fully described below). Master netting arrangements exist with each counterparty that provide for the net settlement (in the settlement month) of all contracts through a single payment. As applicable, management has elected to reflect the net amounts in its balance sheets. No outstanding collateral associated with the Swaps existed during any period presented in the above table. Pursuant to regulatory deferral accounting treatment for rate-regulated entities, unrealized gains and losses in fair value of the Swaps are recorded as a regulatory asset and/or liability. When the Swaps mature, any prior positions held are reversed and the settled position is recorded as an increase or decrease of purchased gas under the related purchased gas adjustment (“PGA”) mechanism in determining deferred PGA balances. Neither changes in fair value, nor settled amounts, of Swaps have a direct effect on earnings or other comprehensive income. The following table presents the amounts paid to and received from counterparties for settlements of matured Swaps. Year ended Year ended Year ended (Thousands of dollars) Paid to counterparties $ 3,100 $ 5,583 $ 7,537 Received from counterparties $ 1,685 $ 726 $ — The following table details the regulatory assets/(liabilities) offsetting the derivatives at fair value in the Consolidated Balance Sheets (thousands of dollars). December 31, 2017 Instrument Balance Sheet Location Net Total Swaps Prepaids and other current assets $ 4,457 Swaps Deferred charges and other assets 1,323 December 31, 2016 Instrument Balance Sheet Location Net Total Swaps Other deferred credits $ (845 ) Swaps Other current liabilities (3,532 ) Fair Value Measurements. The following table sets forth, by level within the three-level fair value hierarchy that ranks the inputs used to measure fair value by their reliability, financial assets and liabilities that were accounted for at fair value (see Note 11 – Pension and Other Post Retirement Benefits for definitions of the levels of the fair value hierarchy): Level 2 – Significant other observable inputs December 31, 2017 December 31, 2016 (Thousands of dollars) Assets at fair value: Prepaids and other current assets – Swaps $ — $ 3,532 Deferred charges and other assets – Swaps — 845 Liabilities at fair value: Other current liabilities – Swaps (4,457 ) — Other deferred credits – Swaps (1,323 ) — Net Assets (Liabilities) $ (5,780 ) $ 4,377 No financial assets or liabilities associated with the Swaps, which were accounted for at fair value, fell within Level 1 or Level 3 of the fair value hierarchy. With regard to the fair values of assets associated with pension and postretirement benefit plans, refer to Note 11 – Pension and Other Post Retirement Benefits . |
Segment Information
Segment Information | 12 Months Ended |
Dec. 31, 2017 | |
Segment Reporting [Abstract] | |
Segment Information | Note 15 – Segment Information The Company’s operating segments are determined based on the nature of their activities. The natural gas operations segment is engaged in the business of purchasing, distributing, and transporting natural gas. Revenues are generated from the distribution and transportation of natural gas. The construction services segment is primarily engaged in the business of providing utility companies with trenching and installation, replacement, and maintenance services for energy distribution systems, and providing industrial construction solutions. Over 99% of the total Company’s long-lived assets are in the United States. The accounting policies of the reported segments are the same as those described within Note 1 – Summary of Significant Accounting Policies . Centuri accounts for the services provided to Southwest at contractual prices at contract inception. Accounts receivable for these services, which are not eliminated during consolidation, are presented in the table below (in thousands). December 31, 2017 December 31, 2016 Accounts receivable for Centuri services $ 12,987 $ 10,585 The following table presents the amount of revenues for both segments by geographic area (thousands of dollars): December 31, December 31, December 31, Revenues (a) United States $ 2,345,134 $ 2,256,600 $ 2,289,133 Canada 203,658 203,890 174,492 Total $ 2,548,792 $ 2,460,490 $ 2,463,625 (a) Revenues are attributed to countries based on the location of customers. The Company has two reportable segments: natural gas operations and construction services. Southwest has a single reportable segment that is referred to herein as the natural gas operations segment of the Company. In order to reconcile to net income as disclosed in the Consolidated Statements of Income, an Other column is included associated with impacts related to corporate and administrative activities related to Southwest Gas Holdings, Inc. The financial information pertaining to the natural gas operations and construction services segments for each of the three years in the period ended December 31, 2017 is as follows (thousands of dollars): 2017 Gas Construction Other Total Revenues from unaffiliated customers $ 1,302,308 $ 1,149,325 $ — $ 2,451,633 Intersegment sales — 97,159 — 97,159 Total $ 1,302,308 $ 1,246,484 $ — $ 2,548,792 Interest revenue $ 2,784 $ 3 $ — $ 2,787 Interest expense $ 69,733 $ 7,986 $ 345 $ 78,064 Depreciation and amortization $ 201,922 $ 49,029 $ — $ 250,951 Income tax expense $ 63,135 $ 2,390 $ (437 ) $ 65,088 Segment net income $ 156,818 $ 38,360 $ (1,337 ) $ 193,841 Segment assets $ 5,482,669 $ 752,496 $ 1,901 $ 6,237,066 Capital expenditures $ 560,448 $ 63,201 $ — $ 623,649 2016 Gas Construction Other Total Revenues from unaffiliated customers $ 1,321,412 $ 1,040,957 $ — $ 2,362,369 Intersegment sales — 98,121 — 98,121 Total $ 1,321,412 $ 1,139,078 $ — $ 2,460,490 Interest revenue $ 1,848 $ 1 $ — $ 1,849 Interest expense $ 66,997 $ 6,663 $ — $ 73,660 Depreciation and amortization $ 233,463 $ 55,669 $ — $ 289,132 Income tax expense $ 58,584 $ 19,884 $ — $ 78,468 Segment net income $ 119,423 $ 32,618 $ — $ 152,041 Segment assets $ 5,001,756 $ 579,370 $ — $ 5,581,126 Capital expenditures $ 457,120 $ 72,411 $ — $ 529,531 2015 Gas Construction Other Total Revenues from unaffiliated customers $ 1,454,639 $ 904,870 $ — $ 2,359,509 Intersegment sales — 104,116 — 104,116 Total $ 1,454,639 $ 1,008,986 $ — $ 2,463,625 Interest revenue $ 1,754 $ 419 $ — $ 2,173 Interest expense $ 64,095 $ 7,784 $ — $ 71,879 Depreciation and amortization $ 213,455 $ 56,656 $ — $ 270,111 Income tax expense $ 61,355 $ 18,547 $ — $ 79,902 Segment net income $ 111,625 $ 26,692 $ — $ 138,317 Segment assets $ 4,822,845 $ 535,840 $ — $ 5,358,685 Capital expenditures $ 438,289 $ 49,711 $ — $ 488,000 |
Quarterly Financial Data
Quarterly Financial Data | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Quarterly Financial Data | Note 16 – Quarterly Financial Data (Unaudited) Quarter Ended March 31 June 30 September 30 December 31 (Thousands of dollars, except per share amounts) 2017 Southwest Gas Holdings, Inc.: Operating revenues $ 654,737 $ 560,469 $ 593,153 $ 740,433 Operating income 119,492 43,408 30,132 130,668 Net income 69,005 18,121 10,420 96,396 Net income attributable to Southwest Gas Holdings, Inc. 69,308 17,864 10,204 96,465 Basic earnings per common share (1) 1.46 0.38 0.21 2.00 Diluted earnings per common share (1) 1.45 0.37 0.21 2.00 Southwest Gas Corporation: Operating revenues $ 462,602 $ 260,162 $ 213,059 $ 366,485 Operating income 131,067 27,489 5,065 113,029 Net income (loss) 76,938 9,522 (4,024 ) 74,382 2016 Southwest Gas Holdings, Inc.: (2) Operating revenues $ 731,248 $ 547,748 $ 539,969 $ 641,525 Operating income 134,096 28,116 15,539 117,963 Net income 75,355 9,099 2,907 65,694 Net income attributable to Southwest Gas Holdings, Inc. 75,446 8,943 2,472 65,180 Basic earnings per common share (1) 1.59 0.19 0.05 1.37 Diluted earnings per common share (1) 1.58 0.19 0.05 1.36 Southwest Gas Corporation: (2) (3) Operating revenues Continuing operations $ 525,100 $ 255,648 $ 200,179 $ 340,485 Discontinued operations – construction services 206,148 292,100 339,790 301,040 Total $ 731,248 $ 547,748 $ 539,969 $ 641,525 Operating income (loss) Continuing operations $ 135,945 $ 15,269 $ (10,231 ) $ 95,745 Discontinued operations – construction services (1,849 ) 12,847 25,770 22,218 Total $ 134,096 $ 28,116 $ 15,539 $ 117,963 Net income (loss) Continuing operations $ 77,583 $ 2,358 $ (12,405 ) $ 51,887 Discontinued operations – construction services (2,137 ) 6,585 14,877 13,293 Total $ 75,446 $ 8,943 $ 2,472 $ 65,180 Quarter Ended March 31 June 30 September 30 December 31 2015 Southwest Gas Holdings, Inc.: (2) Operating revenues $ 734,220 $ 538,604 $ 505,396 $ 685,405 Operating income 129,556 25,047 16,143 117,586 Net income (loss) 71,879 5,063 (4,210 ) 66,698 Net income attributable to Southwest Gas Holdings, Inc. 71,983 4,949 (4,734 ) 66,119 Basic earnings per common share (1) 1.54 0.11 (0.10 ) 1.40 Diluted earnings per common share (1) 1.53 0.10 (0.10 ) 1.38 Southwest Gas Corporation: (2) (3) Operating revenues Continuing operations $ 553,115 $ 286,643 $ 219,420 $ 395,461 Discontinued operations – construction services 181,105 251,961 285,976 289,944 Total $ 734,220 $ 538,604 $ 505,396 $ 685,405 Operating income (loss) Continuing operations $ 137,171 $ 12,958 $ (9,274 ) $ 93,928 Discontinued operations – construction services (7,615 ) 12,089 25,417 23,658 Total $ 129,556 $ 25,047 $ 16,143 $ 117,586 Net income (loss) Continuing operations $ 78,921 $ (657 ) $ (18,939 ) $ 52,300 Discontinued operations – construction services (6,938 ) 5,606 14,205 13,819 Total $ 71,983 $ 4,949 $ (4,734 ) $ 66,119 (1) The sum of quarterly earnings (loss) per average common share may not equal the annual earnings (loss) per share due to the ongoing change in the weighted-average number of common shares. (2) Refer to Notes 1 and 18. Effective 2017, Southwest Gas Holdings, Inc. (“Company) is the successor equity issuer to Southwest Gas Corporation (“Southwest”). Both Southwest and Centuri became subsidiaries of the Company. (3) Periods prior to 2017 depict Centuri amounts as discontinued operations of Southwest. The demand for natural gas is seasonal, and it is the opinion of management that comparisons of earnings for interim periods do not reliably reflect overall trends and changes in operations. Also, the timing of general rate relief can have a significant impact on earnings for interim periods. |
Construction Services Noncontro
Construction Services Noncontrolling Interests | 12 Months Ended |
Dec. 31, 2017 | |
Noncontrolling Interest [Abstract] | |
Construction Services Noncontrolling Interests | Note 17 – Construction Services Noncontrolling Interests In conjunction with the acquisition of the Canadian construction businesses in October 2014, the previous owners of the acquired companies retained a 3.4% equity interest in Centuri, which, subject to an eligibility timeline, would have been redeemable (in its entirety) at the election of the noncontrolling parties beginning in July 2022. In August 2017, in advance of when otherwise eligible, the parties agreed to a current redemption. Southwest Gas Holdings, Inc. paid $23 million to the previous owners, thereby acquiring the remaining 3.4% equity interest in Centuri. Accordingly, Centuri is now a wholly owned subsidiary of the Company. The following depicts changes to the balance of the redeemable noncontrolling interest between the indicated periods. Redeemable (Thousands of dollars): Balance, December 31, 2016 $ 22,590 Net Income (loss) attributable to redeemable noncontrolling interest 248 Foreign currency exchange translation adjustment 11 Centuri distribution to redeemable noncontrolling interest (204 ) Adjustment to redemption value 355 Redemption of Centuri shares from noncontrolling parties (23,000 ) Balance, December 31, 2017 $ — Centuri also holds a 65% interest in a venture to market natural gas engine-driven heating, ventilating, and air conditioning (“HVAC”) technology and products. Centuri consolidates the entity (IntelliChoice Energy, LLC) as a majority-owned subsidiary. The interest is immaterial to the consolidated financial statements, but is identified as the Noncontrolling interest within Total equity on the Company’s Consolidated Balance Sheets. |
Reorganization Impacts - Discon
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation | 12 Months Ended |
Dec. 31, 2017 | |
Restructuring and Related Activities [Abstract] | |
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation | Note 18 – Reorganization Impacts – Discontinued Operations Solely Related to Southwest Gas Corporation In association with the January 2017 holding company reorganization, no substantive change occurred with regard to the Company’s business segments on the whole. Centuri operations remain part of continuing operations of the controlled group of companies, and financial information related to Centuri continues to be included in consolidated financial statements of Southwest Gas Holdings, Inc. While Centuri has since expanded its footprint with the Neuco acquisition (See Note 19 – Acquisition of Construction Services Business ), its core business has remained consistent between 2016 and 2017. As part of the holding company reorganization, however, Centuri is no longer a subsidiary of Southwest; whereas historically, Centuri had been a direct subsidiary of Southwest. To give effect to this change, the consolidated financial statements related to Southwest Gas Corporation, which are separately included in this report, depict Centuri-related amounts as discontinued operations for periods prior to January 2017. Due to the discontinued operations accounting reflection, the following disclosures provide additional information regarding the assets, liabilities, equity, revenues, and expenses of Centuri which are shown as discontinued operations on the consolidated financial statements (as specifically referred to below) of Southwest Gas Corporation for periods prior to the beginning of 2017. The following table presents the major categories of assets and liabilities within the amounts reported as discontinued operations – construction services in the Consolidated Balance Sheet of Southwest Gas Corporation: December 31, 2016 (Thousands of dollars) Assets: Other property and investments $ 233,774 Cash and cash equivalents 9,042 Accounts receivable, net of allowances 173,300 Prepaids and other current assets 10,470 Goodwill 129,888 Other noncurrent assets 22,897 Discontinued operations – construction services – assets $ 579,371 Liabilities: Current maturities of long-term debt $ 25,101 Accounts payable 46,440 Other current liabilities 74,518 Long-term debt, less current maturities 174,903 Deferred income taxes and other deferred credits 59,653 Discontinued operations – construction services – liabilities $ 380,615 The following table presents the components of the Discontinued operations – construction services non-owner December 31, 2016 (Thousands of dollars) Construction services equity $ (4,390 ) Construction services noncontrolling interest (2,217 ) Construction services redeemable noncontrolling interest 22,590 Discontinued operations – construction services non-owner $ 15,983 The following table presents the major income statement components of discontinued operations – construction services reported in the Consolidated Income Statements of Southwest Gas Corporation: Results of Construction Services Year Ended December 31, 2016 2015 (Thousands of dollars) Construction revenues $ 1,139,078 $ 1,008,986 Operating expenses: Construction expenses 1,024,423 898,781 Depreciation and amortization 55,669 56,656 Operating income 58,986 53,549 Other income (deductions) 1,193 587 Net interest deductions 6,663 7,784 Income before income taxes 53,516 46,352 Income tax expense 19,884 18,547 Net income 33,632 27,805 Net income attributable to noncontrolling interests 1,014 1,113 Discontinued operations – construction services – net income $ 32,618 $ 26,692 |
Acquisition of Construction Ser
Acquisition of Construction Services Business | 12 Months Ended |
Dec. 31, 2017 | |
Business Combinations [Abstract] | |
Acquisition of Construction Services Business | Note 19 – Acquisition of Construction Services Business As indicated in Note 1 – Summary of Significant Accounting Policies, under Consolidation Note 8 – Long-Term Debt . The Company is currently performing a detailed valuation analysis of the assets and liabilities of the acquired company, which was substantially completed during the fourth quarter of 2017. Certain payments were estimated as of the acquisition date and will be adjusted when finally paid in the first half of 2018. The necessary analysis will consider acquired intangibles including customer relationships and trade names. Based on preliminary results, a substantial majority of the purchase price will be allocated to goodwill and other finite-lived and indefinite-lived intangibles. Assets acquired and liabilities assumed in the transaction were recorded, generally, at their acquisition date fair values. Transaction costs associated with the acquisition were expensed as incurred. The Company’s allocation of the purchase price was based on an evaluation of the appropriate fair values and represented management’s best estimate based on available data (including market data, data regarding customers of the acquired businesses, terms of acquisition-related agreements, analysis of historical and projected results, and other types of data). The analysis included consideration of types of intangibles that were acquired, including non-competition The preliminary estimated fair values of assets acquired and liabilities assumed as of November 1, 2017, are as follows (in millions of dollars): Cash and cash equivalents $ 0.8 Contracts receivable 18.3 Other receivables 5.4 Property, plant and equipment 15.1 Prepaid expenses and deposits 1.7 Intangible assets 44.8 Goodwill 32.0 Total assets acquired 118.1 Current liabilities (18.5 ) Other long-term liabilities (0.3 ) Net assets acquired $ 99.3 Acquired contracts receivable and other receivables are expected to be collected. The preliminary allocation of the purchase price of Neuco was accounted for in accordance with applicable accounting guidance. Goodwill, which is generally not deductible for tax purposes, consists of the value associated with the assembled workforce and consolidation of operations. However, as the business of Neuco was acquired via asset purchase for tax purposes, the $32 million of tax-basis non-competition 3-year 10-year 2018 $ 3,641 2019 3,724 2020 3,669 2021 3,391 2022 3,391 The unaudited pro forma consolidated financial information for fiscal 2017 and fiscal 2016 (assuming the acquisition of Neuco occurred as of the beginning fiscal 2016) is as follows (in thousands of dollars, except per share amounts): Year Ended December 31, 2017 2016 Total operating revenues $ 2,639,452 $ 2,556,124 Net income attributable to Southwest Gas Holdings, Inc. $ 203,245 $ 156,108 Basic earnings per share $ 4.24 $ 3.29 Diluted earnings per share $ 4.24 $ 3.26 Acquisition costs of $2.6 million that were incurred during 2017, and included in construction expenses in the Consolidated Statements of Income, were excluded from the 2017 unaudited pro forma consolidated financial information shown above and included in the 2016 amounts. No material nonrecurring pro forma adjustments directly attributable to the business combination were included in the unaudited pro forma consolidated financial information. The pro forma financial information includes assumptions and adjustments made to incorporate various items including, but not limited to, additional interest expense and depreciation and amortization expense, and tax effects, as appropriate. The pro forma financial information has been prepared for comparative purposes only, and is not intended to be indicative of what the Company’s results would have been had the acquisition occurred at the beginning of the periods presented or of the results which may occur in the future, for a number of reasons. These reasons include, but are not limited to, differences between the assumptions used to prepare the pro forma information, potential cost savings from operating efficiencies, and the impact of incremental costs incurred in integrating the businesses. Actual results from Neuco operations, excluding deal costs incurred by Centuri, included in the Consolidated Statements of Income since the date of acquisition are as follows (in thousands of dollars): Year ended Construction revenues $ 17,182 Net income attributable to Neuco 2,772 To facilitate the acquisition, in November 2017, Centuri amended and restated its senior secured credit and term loan facility, increasing the borrowing capacity from $300 million to $450 million. The amended and restated facility expires in November 2022. See Note 8 – Long-Term Debt for information regarding the amended and restated credit and term loan facility. |
Summary of Significant Accoun28
Summary of Significant Accounting Policies (Policies) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Nature of Operations | Nature of Operations. Note 17 – Construction Services Noncontrolling Interests for additional information. In January 2017, a previously contemplated and approved reorganization under a holding company structure was made effective. The reorganization was designed to provide further separation between regulated and unregulated businesses, and to provide additional financing flexibility. Coincident with the effective date of the reorganization, existing shareholders of Southwest Gas Corporation became shareholders of Southwest Gas Holdings, Inc., on a one-for-one Southwest is engaged in the business of purchasing, distributing, and transporting natural gas for customers in portions of Arizona, Nevada, and California. Public utility rates, practices, facilities, and service territories of Southwest are subject to regulatory oversight. The timing and amount of rate relief can materially impact results of operations. Natural gas purchases and the timing of related recoveries can materially impact liquidity. Results for the natural gas operations segment are higher during winter periods due to the seasonality incorporated in its regulatory rate structures. Centuri is a comprehensive construction services enterprise dedicated to meeting the growing demands of North American utilities, energy and industrial markets. Centuri derives revenue from installation, replacement, repair, and maintenance of energy distribution systems, and developing industrial construction solutions. Centuri operations are generally conducted under the business names of NPL Construction Co. (“NPL”), Canyon Pipeline Construction, Inc. (“Canyon”), NPL Canada Ltd. (“NPL Canada”, formerly Link-Line Contractors Ltd.), W.S. Nicholls Construction, Inc. (“W.S. Nicholls”), and Brigadier Pipelines Inc. (“Brigadier”). Typically, Centuri revenues are lowest during the first quarter of the year due to unfavorable winter weather conditions. Operating revenues typically improve as more favorable weather conditions occur during the summer and fall months. Centuri acquired New England Utility Constructors, Inc. (“Neuco”) in November 2017, thereby expanding its core services in the Northeast region of the United States. See Note 19 – Acquisition of Construction Services Business for more information. |
Basis of Presentation | Basis of Presentation. Note 18 – Reorganization Impacts – Discontinued Operations Solely Related to Southwest Gas Corporation , and include both current and non-current Prior to the August 2017 purchase of the residual 3.4% interest in Centuri, earnings associated with the 3.4% interest were attributable to the previous noncontrolling parties and therefore, not included in the earnings of the Company. Following the purchase date, 100% of Centuri earnings are attributable to the Company. No substantive change has occurred with regard to the Company’s business segments on the whole as a result of the foregoing organizational changes. Centuri operations continue to be part of continuing operations and included in the consolidated financial statements of Southwest Gas Holdings, Inc. While Centuri has expanded its footprint with the Neuco acquisition, its core business has remained consistent. Southwest Gas Corporation consists of a single segment – natural gas operations. |
Consolidation | Consolidation. Centuri, through its subsidiaries, holds a 65% interest in a venture to market natural gas engine-driven heating, ventilating, and air conditioning (“HVAC”) technology and products. Centuri consolidates the entity (IntelliChoice Energy, LLC). Centuri, through its subsidiaries, holds a 50% interest in W.S. Nicholls Western Construction LTD. (“Western”), a Canadian construction services company that is a variable interest entity. Centuri determined that it is not the primary beneficiary of the entity due to a shared-power structure; therefore, Centuri does not consolidate the entity and has recorded its investment, and results related thereto, using the equity method. The investment in Western totaled $12.7 million and $10.8 million at December 31, 2017 and 2016, respectively. Both periods include the impacts of foreign currency exchange translation adjustments. No dividends were received from Western during 2017. Dividends of $500,000 were received from Western in 2016. In 2017, a management fee was paid by Western to its partners, including W.S. Nicholls, in accordance with underlying agreements. The equity method investment in Western is included in Other Property and Investments in the Consolidated Balance Sheets of the Company. Centuri’s maximum exposure to loss as a result of its involvement with Western is estimated at $49.3 million. The estimated maximum exposure to loss represents the maximum loss that would be absorbed by Centuri in the event that all of the assets of Western were deemed to be worthless. Centuri recorded earnings of $1.1 million from this investment in 2017, which is included in Other Income (deductions) in the Consolidated Statements of Income. |
Net Utility Plant | Net Utility Plant. Management determined that utility-related acquisition adjustments were immaterial to both the Company and Southwest as of December 31, 2017 and December 31, 2016, and therefore, combined related amounts with gas plant. Management has, therefore, reclassified the previous year comparative balance sheet presentation to be on the same basis as the most recently completed year-end |
Other Property and Investments | Other Property and Investments. Southwest Gas Corporation: 2017 2016 Net cash surrender value of COLI policies $ 117,341 $ 106,744 Other property 1,773 1,825 Total Southwest Gas Corporation 119,114 108,569 Centuri property, equipment, and intangibles 554,730 451,114 Centuri accumulated provision for depreciation and amortization (258,906 ) (228,374 ) Other property 13,242 11,034 Total Southwest Gas Holdings, Inc. $ 428,180 $ 342,343 |
Deferred Purchased Gas Costs | Deferred Purchased Gas Costs. |
Prepaids and Other Current Assets | Prepaids and other current assets |
Income Taxes | Income Taxes. Note 13 – Income Taxes regarding recent tax changes enacted, including the remeasurement of deferred tax balances. For regulatory and financial reporting purposes, investment tax credits (“ITC”) related to gas utility operations are deferred and amortized over the life of related fixed assets. As of December 31, 2017, the Company had cumulative earnings of approximately $13 million of book earnings in its foreign jurisdiction. Management previously asserted and continues to assert that all the earnings of Centuri’s Canadian subsidiaries will be permanently reinvested in Canada. As a result, no U.S. deferred income taxes have been recorded related to cumulative foreign earnings. On December 22, 2017, the legislation referred to as the Tax Cuts and Jobs Act (“TCJA”) was enacted. Substantially all of the provisions of the TCJA are effective for taxable years beginning after December 31, 2017. The TCJA includes extensive changes which significantly impact the taxation of business entities, including specific provisions related to regulated public utilities. The more significant changes that impact the Company include the reduction in the corporate federal income tax rate from 35% to 21%, and several technical provisions including, among others, limiting the utilization of net operating losses (“NOLs”) arising after December 31, 2017 to 80% of taxable income, with the ability to indefinitely carryforward unutilized NOLs to reduce future taxable income. For 2017, the Company benefited by the reduction in tax rates related to its construction services segment as a result of the required remeasurement of deferred tax balances based on the reduction in enacted rates, reducing income tax expense in the current year. The regulated operations of Southwest experienced other impacts due to its rate-regulation and the accounting treatment prescribed by U.S. GAAP to reflect the economics of the rate-regulation. Approximately $8 million favorably impacted tax expense for Southwest, while remaining reductions in accumulated deferred income tax balances to reflect the remeasurement were reclassified to regulatory liabilities in Other deferred credits on the balance sheets of Southwest and the Company. See Note 5 – Regulatory Assets and Liabilities and Note 13 – Income Taxes for further information. |
Cash and Cash Equivalents | Cash and Cash Equivalents. Significant non-cash non-cash |
Adoption of Accounting Standards Update | Adoption of Accounting Standards Update (“ASU”) No. 2016-09. No. 2016-09 Under the new guidance, the Company can withhold any amount between the minimum and maximum individual statutory tax rates and still treat the entire award as equity. The Company intends to administer withholding such that awards under stock compensation programs will continue to be treated as equity awards. In addition to the above, the update requires all income tax-related Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value are required to be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. No previously unrecognized tax benefits existed as a result of these changes; therefore, no cumulative effect adjustment to the opening retained earnings was required. |
Goodwill | Goodwill. Note 19 – Acquisition of Construction Services Business ) was considered an asset purchase for tax purposes. As a result, goodwill associated with Neuco is expected to be deductible for those same purposes. Southwest Construction Services Total (In thousands of dollars) December 31, 2016 $ 10,095 $ 129,888 $ 139,983 Additional goodwill from New England Utility Constructors, Inc. acquisition — 32,028 32,028 Foreign currency translation adjustment — 7,303 7,303 December 31, 2017 $ 10,095 $ 169,219 $ 179,314 |
Intangible Assets | Intangible Assets Non-utility December 31, 2017 Gross Carrying Accumulated Net Carrying Customer relationships $ 76,254 $ (6,743 ) $ 69,511 Trade names and trademarks 13,754 (4,080 ) 9,674 Noncompete agreement 2,060 (543 ) 1,517 Total $ 92,068 $ (11,366 ) $ 80,702 December 31, 2016 Customer relationships $ 34,033 $ (3,906 ) $ 30,127 Trade names and trademarks 9,349 (2,565 ) 6,784 Customer contracts backlog 1,656 (1,656 ) — Noncompete agreement 1,029 (271 ) 758 Total $ 46,067 $ (8,398 ) $ 37,669 The above intangible assets are included in Other property and investments in the Southwest Gas Holdings, Inc. Consolidated Balance Sheets. The estimated future amortization of the intangible assets for the next five years is as follows (in thousands): 2018 $ 6,835 2019 6,240 2020 6,114 2021 5,711 2022 5,626 See Note 2 – Utility Plant and Leases for additional information regarding natural gas operations intangible assets . Note 19 – Acquisition of Construction Services Business includes detailed information about intangible assets purchased in the Neuco acquisition. |
Accumulated Removal Costs | Accumulated Removal Costs. |
Gas Operating Revenues | Gas Operating Revenues. Note 3 – Revenue for additional information regarding natural gas operating revenues. Southwest acts as an agent for state and local taxing authorities in the collection and remission of a variety of taxes, including sales and use taxes and surcharges. These taxes are not included in gas operating revenues. Management uses the net classification method to report taxes collected from customers to be remitted to governmental authorities. |
Construction Revenues | Construction Revenues. Note 3 – Revenue for additional information regarding construction revenues. Centuri is required to collect taxes imposed by various governmental agencies on the work performed by Centuri for its customers. These taxes are not included in construction revenues. Management uses the net classification method to report taxes collected from customers to be remitted to governmental authorities. |
Construction Expenses | Construction Expenses. job-related |
Net Cost of Gas Sold | Net Cost of Gas Sold. |
Operations and Maintenance Expense | Operations and Maintenance Expense. |
Depreciation and Amortization | Depreciation and Amortization. Accumulated Removal Costs |
Allowance for Funds Used During Construction ("AFUDC") | Allowance for Funds Used During Construction (“AFUDC”). 2017 2016 2015 (In thousands) AFUDC: Debt portion $ 1,666 $ 1,175 $ 1,666 Equity portion 2,296 2,289 3,008 AFUDC capitalized as part of utility plant $ 3,962 $ 3,464 $ 4,674 AFUDC rate 5.95 % 7.35 % 7.32 % |
Other Income (Deductions) | Other Income (Deductions). 2017 2016 2015 Southwest Gas Corporation – natural gas operations segment: Change in COLI policies $ 10,300 $ 7,400 $ (500 ) Interest income 2,784 1,848 1,754 Equity AFUDC 2,296 2,289 3,008 Miscellaneous income and (expense) (2,344 ) (3,261 ) (1,970 ) Southwest Gas Corporation – total other income (deductions) 13,036 8,276 2,292 Construction services segment: Interest income 3 1 419 Foreign transaction gain (loss) (754 ) (22 ) (824 ) Equity in earnings of unconsolidated investment – Western 1,052 69 310 Miscellaneous income and (expense) 44 1,145 682 Centuri – total other income (deductions) 345 1,193 587 Corporate and administrative 13 — — Consolidated Southwest Gas Holdings, Inc. – total other income (deductions) $ 13,394 $ 9,469 $ 2,879 Included in the table above is the change in cash surrender values of company-owned life insurance (“COLI”) policies (including net death benefits recognized). These life insurance policies on members of management and other key employees are used by the Company and Southwest to indemnify against the loss of talent, expertise, and knowledge, as well as to provide indirect funding for certain nonqualified benefit plans. Current tax regulations provide for tax-free |
Foreign Currency Translation | Foreign Currency Translation. |
Earnings Per Share | Earnings Per Share. 2017 2016 2015 (In thousands) Average basic shares 47,965 47,469 46,992 Effect of dilutive securities: Stock options — 1 8 Management Incentive Plan shares 8 124 171 Restricted stock units (1) 18 220 212 Average diluted shares 47,991 47,814 47,383 (1) The number of securities granted for 2017 includes 7,000 performance shares, the total of which was derived by assuming that target performance will be achieved during the relevant performance period. |
Recently Issued Accounting Standards Updates | Recently Issued Accounting Standards Updates Note 3 – Revenue . In January 2016, the FASB issued the update “Financial Instruments – Overall (Subtopic 825-10): In February 2016, the FASB issued the update “Leases (Topic 842).” Under the update, lessees will be required to recognize the following for all leases (with the exception of short-term leases) at the commencement date: • A lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and • A right-of-use Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. Though companies have historically been required to make disclosures regarding leases and of associated contractual obligations, leases (with terms longer than a year) will no longer exist off-balance In June 2016, the FASB issued the update “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The update amends guidance on reporting credit losses for financial assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, the update eliminates the “probable” threshold for initial recognition of credit losses in current U.S. GAAP and, instead, requires an entity to reflect its current estimate of all expected credit losses. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net amount expected to be collected. For available for sale debt securities, credit losses should be measured in a manner similar to current U.S. GAAP, however the update will require that credit losses be presented as an allowance rather than as a write-down. This update affects entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The update affects loans, debt securities, trade receivables, net investments in leases, off-balance In August 2016, the FASB issued the update “Classification of Certain Cash Receipts and Cash Payments.” This update addresses the following specific cash flow issues: debt prepayment or debt extinguishment costs; settlement of zero-coupon In October 2016, the FASB issued the update “Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory.” This update eliminates the current U.S. GAAP exception for all intra-entity sales of assets other than inventory. As a result, a reporting entity would recognize the tax expense from the sale of the asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax In January 2017, the FASB issued the update “Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” The update eliminates Step 2 from the goodwill impairment test. The annual, or interim, goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. In addition, income tax effects from any tax-deductible In March 2017, the FASB issued the update “Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” The update applies to all employers that offer employee benefits under defined benefit pension plans, other postretirement benefit plans, or other types of benefits accounted for under Topic 715, Compensation – Retirement Benefits. The update requires that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, and be appropriately described. The update also allows only the service cost component (and not the other components of periodic benefit costs) to be eligible for capitalization when applicable, making no exception for specialized industries, including rate-regulated Southwest is a rate-regulated utility offering pension and postretirement benefits to retired employees. It is anticipated that Southwest would continue to request recovery of the total costs of defined benefit plans in rate applications filed with its various regulatory bodies. Rate-regulated entities providing utility and transmission services have historically capitalized a portion of periodic benefit costs (including non-service non-service non-service non-service |
Subsequent Events | Subsequent Events. |
Summary of Significant Accoun29
Summary of Significant Accounting Policies (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Accounting Policies [Abstract] | |
Schedule of Other Property and Investments | Other property and investments on the Southwest and Company Condensed Consolidated Balance Sheets includes (thousands of dollars): Southwest Gas Corporation: 2017 2016 Net cash surrender value of COLI policies $ 117,341 $ 106,744 Other property 1,773 1,825 Total Southwest Gas Corporation 119,114 108,569 Centuri property, equipment, and intangibles 554,730 451,114 Centuri accumulated provision for depreciation and amortization (258,906 ) (228,374 ) Other property 13,242 11,034 Total Southwest Gas Holdings, Inc. $ 428,180 $ 342,343 |
Schedule of Goodwill | Southwest Construction Services Total (In thousands of dollars) December 31, 2016 $ 10,095 $ 129,888 $ 139,983 Additional goodwill from New England Utility Constructors, Inc. acquisition — 32,028 32,028 Foreign currency translation adjustment — 7,303 7,303 December 31, 2017 $ 10,095 $ 169,219 $ 179,314 |
Summary of Intangible Assets | Centuri has $80.7 million and $37.7 million of intangible assets at December 31, 2017 and 2016, respectively, as detailed in the following table (thousands of dollars): December 31, 2017 Gross Carrying Accumulated Net Carrying Customer relationships $ 76,254 $ (6,743 ) $ 69,511 Trade names and trademarks 13,754 (4,080 ) 9,674 Noncompete agreement 2,060 (543 ) 1,517 Total $ 92,068 $ (11,366 ) $ 80,702 December 31, 2016 Customer relationships $ 34,033 $ (3,906 ) $ 30,127 Trade names and trademarks 9,349 (2,565 ) 6,784 Customer contracts backlog 1,656 (1,656 ) — Noncompete agreement 1,029 (271 ) 758 Total $ 46,067 $ (8,398 ) $ 37,669 |
Schedule of Estimated Future Amortization of Intangible Assets | The above intangible assets are included in Other property and investments in the Southwest Gas Holdings, Inc. Consolidated Balance Sheets. The estimated future amortization of the intangible assets for the next five years is as follows (in thousands): 2018 $ 6,835 2019 6,240 2020 6,114 2021 5,711 2022 5,626 |
Schedule of Capitalized and Debt Portion of AFUDC | Utility plant construction costs, including AFUDC, are recovered in authorized rates through depreciation when completed projects are placed into operation, and general rate relief is requested and granted. 2017 2016 2015 (In thousands) AFUDC: Debt portion $ 1,666 $ 1,175 $ 1,666 Equity portion 2,296 2,289 3,008 AFUDC capitalized as part of utility plant $ 3,962 $ 3,464 $ 4,674 AFUDC rate 5.95 % 7.35 % 7.32 % |
Other Income (Deductions) | The following table provides the composition of significant items included in Other income (deductions) on the consolidated statements of income (thousands of dollars): 2017 2016 2015 Southwest Gas Corporation – natural gas operations segment: Change in COLI policies $ 10,300 $ 7,400 $ (500 ) Interest income 2,784 1,848 1,754 Equity AFUDC 2,296 2,289 3,008 Miscellaneous income and (expense) (2,344 ) (3,261 ) (1,970 ) Southwest Gas Corporation – total other income (deductions) 13,036 8,276 2,292 Construction services segment: Interest income 3 1 419 Foreign transaction gain (loss) (754 ) (22 ) (824 ) Equity in earnings of unconsolidated investment – Western 1,052 69 310 Miscellaneous income and (expense) 44 1,145 682 Centuri – total other income (deductions) 345 1,193 587 Corporate and administrative 13 — — Consolidated Southwest Gas Holdings, Inc. – total other income (deductions) $ 13,394 $ 9,469 $ 2,879 |
Schedule of Earnings Per Share, Basic and Diluted | A reconciliation of the denominator used in the Basic and Diluted EPS calculations is shown in the following table. 2017 2016 2015 (In thousands) Average basic shares 47,965 47,469 46,992 Effect of dilutive securities: Stock options — 1 8 Management Incentive Plan shares 8 124 171 Restricted stock units (1) 18 220 212 Average diluted shares 47,991 47,814 47,383 (1) The number of securities granted for 2017 includes 7,000 performance shares, the total of which was derived by assuming that target performance will be achieved during the relevant performance period. |
Utility Plant and Leases (Table
Utility Plant and Leases (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Leases [Abstract] | |
Schedule of Net Utility Plant | Net utility plant as of December 31, 2017 and 2016 was as follows (thousands of dollars): December 31, 2017 2016 Gas plant: Storage $ 25,019 $ 24,614 Transmission 363,396 349,981 Distribution 5,600,769 5,198,531 General 396,252 382,084 Software and software-related intangibles 230,030 224,260 Other 14,178 14,290 6,629,644 6,193,760 Less: accumulated depreciation (2,231,242 ) (2,172,966 ) Construction work in progress 125,248 111,177 Net utility plant $ 4,523,650 $ 4,131,971 |
Schedule of Depreciation and Amortization Expense | Depreciation and amortization expense on gas plant, including intangibles, was as follows (thousands of dollars): 2017 2016 2015 Depreciation and amortization expense $ 187,075 $ 214,037 $ 201,233 |
Schedule of Rental Payments for Operating Leases | The table below presents Southwest’s and Centuri’s rental and lease payments that are included in operating expenses (in thousands): 2017 2016 2015 Southwest Gas Corporation $ 4,926 $ 4,357 $ 4,186 Centuri 62,310 53,956 45,849 Consolidated rental payments/lease expense $ 67,236 $ 58,313 $ 50,035 |
Schedule of Future Minimum Lease Payments for Operating Leases | The following is a schedule of future minimum lease payments for operating leases (with initial or remaining terms in excess of one year) as of December 31, 2017 (thousands of dollars): Consolidated Southwest Centuri Total 2018 $ 1,538 $ 7,297 $ 8,835 2019 886 7,188 8,074 2020 714 5,157 5,871 2021 627 3,828 4,455 2022 299 3,364 3,663 Thereafter 116 9,530 9,646 Total minimum lease payments $ 4,180 $ 36,364 $ 40,544 |
Schedule of Capital Leases of Equipment | The amounts associated with capital leases of equipment as of December 31, 2017 and 2016 are as follows (thousands of dollars): December 31, 2017 2016 Capital leased assets, gross $ 2,159 $ 3,189 Less: accumulated amortization (1,000 ) (1,172 ) Capital leased assets, net $ 1,159 $ 2,017 |
Schedule of Future Minimum Lease Payments for Capital Leases | The following is a schedule of future minimum lease payments for non-cancelable Year Ending December 31, 2018 $ 709 2019 233 2020 191 2021 — 2022 — Thereafter — 1,133 Less: amount representing interest (84 ) Total minimum lease payments $ 1,049 |
Receivables and Related Allow31
Receivables and Related Allowances (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Receivables [Abstract] | |
Schedule of Accounts Receivable | The table below contains information about the gas utility customer accounts receivable balance (net of allowance) at December 31, 2017 and 2016, and the percentage of customers in each of the three states. December 31, 2017 December 31, 2016 Gas utility customer accounts receivable balance (in thousands) $ 119,444 $ 111,320 |
Schedule of Percent of Customers by State | December 31, 2017 Percent of customers by state Arizona 53 % Nevada 37 % California 10 % |
Schedule of Allowance for Uncollectibles | Activity in the allowance account for uncollectibles is summarized as follows (thousands of dollars): Allowance for Balance, December 31, 2014 $ 2,255 Additions charged to expense 4,113 Accounts written off, less recoveries (4,098 ) Balance, December 31, 2015 2,270 Additions charged to expense 3,264 Accounts written off, less recoveries (3,010 ) Balance, December 31, 2016 2,524 Additions charged to expense 2,310 Accounts written off, less recoveries (2,723 ) Balance, December 31, 2017 $ 2,111 |
Regulatory Assets and Liabili32
Regulatory Assets and Liabilities (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Regulated Operations [Abstract] | |
Schedule of Regulatory Assets and Liabilities | The following table represents existing regulatory assets and liabilities (thousands of dollars): December 31, 2017 2016 Regulatory assets: Accrued pension and other postretirement benefit costs (1) $ 391,403 $ 379,063 Unrealized net loss on non-trading 5,780 — Deferred purchased gas costs (3) 14,581 2,608 Accrued purchased gas costs (4) 17,000 37,100 Unamortized premium on reacquired debt (5) 20,913 21,975 Accrued absence time (10) 13,870 13,440 Other (6) 68,351 23,557 531,898 477,743 Regulatory liabilities: Deferred purchased gas costs (3) (6,841 ) (90,476 ) Accumulated removal costs (315,000 ) (308,000 ) Unrealized net gain on non-trading — (4,377 ) Unamortized gain on reacquired debt (7) (9,253 ) (9,789 ) Regulatory excess deferred taxes and gross -up (433,908 ) (6,593 ) Other (9) (33,184 ) (18,066 ) Net regulatory assets (liabilities) $ (266,288 ) $ 40,442 (1) Included in Deferred charges and other assets on the Consolidated Balance Sheets. Recovery period is greater than five years. (See Note 11 – Pension and Other Postretirement Benefits (2) The following table details the regulatory assets/(liabilities) offsetting the derivatives (Swaps) at fair value in the Consolidated Balance Sheets (thousands of dollars). The actual amounts, when realized at settlement, become a component of purchased gas costs under Southwest’s purchased gas adjustment (“PGA”) mechanisms. (See Note 14 – Derivatives and Fair Value Measurements Instrument Balance Sheet Location 2017 2016 Swaps Deferred charges and other assets $ 1,323 $ — Swaps Prepaids and other current assets 4,457 — Swaps Other current liabilities — (3,532 ) Swaps Other deferred credits — (845 ) (3) Balance recovered or refunded on an ongoing basis with interest. (4) Included in Prepaids and other current assets on the Consolidated Balance Sheets. Balance recovered or refunded on an ongoing basis. (5) Included in Deferred charges and other assets on the Consolidated Balance Sheets. Recovered over life of debt instruments. (6) The following table details the components of Other regulatory assets which are included in either Prepaids and other current assets or Deferred charges and other assets on the Consolidated Balance Sheets (as indicated). Recovery periods vary. Margin tracking/decoupling mechanisms are alternative revenue programs and revenue associated with under-collections (for the difference between authorized margin levels and amounts billed to customers through rates currently) are recognized as revenue so long as recovery is expected to take place within 24 months. |
Schedule of Components of Other regulatory assets which are included in either Prepaids and other current assets or Deferred charges and other assets on the Consolidated Balance Sheets | Other Regulatory Assets 2017 2016 State mandated public purpose programs (including low income and conservation programs) (a) (e) $ 4,832 $ 7,096 Margin and interest-tracking accounts (a) (e) 42,354 3,517 Infrastructure replacement programs and similar (b) (e) 9,627 6,976 Environmental compliance programs (c) (e) 9,702 4,329 Other (d) 1,836 1,639 $ 68,351 $ 23,557 a) Included in Prepaids and other current assets on the Consolidated Balance Sheets. See Prepaids and other current assets Note 1 – Summary of Significant Accounting Policies b) Included in Deferred charges and other assets on the Consolidated Balance Sheets. c) 2017 included in Prepaids and other current assets on the Consolidated Balance Sheets ($9.2 million) and Deferred charges and other assets on the Consolidated Balance Sheets ($527,000); 2016 included in Prepaids and other current assets on the Consolidated Balance Sheets ($3.8 million) and Deferred charges and other assets on the Consolidated Balance Sheets ($500,000). d) 2017 included in Prepaids and other current assets on the Consolidated Balance Sheets ($531,000) and Deferred charges and other assets on the Consolidated Balance Sheets ($1.3 million); 2016 included in Prepaids and other current assets on the Consolidated Balance Sheets ($622,000) and Deferred charges and other assets on the Consolidated Balance Sheets ($1 million). e) Balance recovered or refunded on an ongoing basis, generally with interest. |
Schedule of Components of Other Regulatory Liabilities which are Included in either Other Current Liabilities or Deferred Credits and Other Liabilities on Consolidated Balance Sheets | Other Regulatory Liabilities 2017 2016 State mandated public purpose programs (including low income and conservation $ (10,213 ) $ (7,101 ) Margin, interest- and property tax-tracking (9,505 ) (3,668 ) Environmental compliance programs (a) (e) (8,574 ) (4,469 ) Regulatory accounts for differences related to pension funding (c) (3,178 ) (2,284 ) Other (d) (e) (1,714 ) (544 ) $ (33,184 ) $ (18,066 ) a) Included in Other current liabilities on the Consolidated Balance Sheets. b) 2017 included in Other current liabilities ($6.6 million) and Other deferred credits and other long-term liabilities ($2.9 million) on the Consolidated Balance Sheets; 2016 included in Other current liabilities on the Consolidated Balance Sheets. c) Included in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets. d) 2017 included in Other current liabilities on the Consolidated Balance Sheets ($1.7 million) and in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets ($9,000); 2016 included in Other current liabilities on the Consolidated Balance Sheets ($536,000) and in Other deferred credits and other long-term liabilities on the Consolidated Balance Sheets ($8,000). e) Balance recovered or refunded on an ongoing basis, generally with interest. |
Other Comprehensive Income an33
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) | Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Thousands of dollars) 2017 2016 2015 Before- Tax Net-of- Before- Tax Net-of- Before- Tax Net-of- Defined benefit pension plans: Net actuarial gain/(loss) $ (43,027 ) $ 10,326 $ (32,701 ) $ (22,770 ) $ 8,652 $ (14,118 ) $ (30,519 ) $ 11,597 $ (18,922 ) Amortization of prior service cost 1,335 (507 ) 828 1,335 (507 ) 828 1,335 (507 ) 828 Amortization of net actuarial (gain)/loss 25,445 (9,669 ) 15,776 27,066 (10,285 ) 16,781 34,381 (13,065 ) 21,316 Regulatory adjustment 12,340 250 12,590 (5,584 ) 2,122 (3,462 ) (5,646 ) 2,146 (3,500 ) Pension plans other comprehensive income (loss) (3,907 ) 400 (3,507 ) 47 (18 ) 29 (449 ) 171 (278 ) Forward-starting interest rate swaps (“FSIRS”) (designated hedging activities): Amounts reclassified into net income 3,344 (1,271 ) 2,073 3,345 (1,270 ) 2,075 3,344 (1,271 ) 2,073 FSIRS other comprehensive income (loss) 3,344 (1,271 ) 2,073 3,345 (1,270 ) 2,075 3,344 (1,271 ) 2,073 Total other comprehensive income (loss) – Southwest Gas Corporation (563 ) (871 ) (1,434 ) 3,392 (1,288 ) 2,104 2,895 (1,100 ) 1,795 Foreign currency translation adjustments: Translation adjustments 1,771 — 1,771 161 — 161 (1,954 ) — (1,954 ) Foreign currency other comprehensive income (loss) 1,771 — 1,771 161 — 161 (1,954 ) — (1,954 ) Total other comprehensive income (loss) – Southwest Gas Holdings, Inc. $ 1,208 $ (871 ) $ 337 $ 3,553 $ (1,288 ) $ 2,265 $ 941 $ (1,100 ) $ (159 ) (1) Tax amounts related to existing before-tax before-tax |
Schedule of Estimated Amounts Amortized from Accumulated Other Comprehensive Income or Regulatory Assets into Net Periodic Benefit Cost | The estimated amounts that will be amortized from accumulated other comprehensive income or regulatory assets into net periodic benefit cost over the next year are summarized below (in thousands): Retirement plan net actuarial loss $ 32,000 SERP net actuarial loss 1,500 PBOP prior service cost 1,300 |
Rollforward of Accumulated Other Comprehensive Income | The following table represents a rollforward of AOCI, presented on the Company’s Consolidated Balance Sheets and its Consolidated Statements of Equity: AOCI—Rollforward (Thousands of dollars) Defined Benefit Plans (Note 11) FSIRS (Note 14) Foreign Currency Items Before-Tax Tax After-Tax Before- Tax After-Tax Before- Tax After-Tax AOCI Beginning Balance AOCI December 31, 2016 $ (57,613 ) $ 21,893 $ (35,720 ) $ (15,999 ) $ 6,080 $ (9,919 ) $ (2,369 ) $ — $ (2,369 ) $ (48,008 ) Net actuarial gain/(loss) (43,027 ) 10,326 (32,701 ) — — — — — — (32,701 ) Translation adjustments — — — — — — 1,771 — 1,771 1,771 Other comprehensive income before reclassifications (43,027 ) 10,326 (32,701 ) — — — 1,771 — 1,771 (30,930 ) FSIRS amounts reclassified from AOCI (1) — — — 3,344 (1,271 ) 2,073 — — — 2,073 Amortization of prior service 1,335 (507 ) 828 — — — — — — 828 Amortization of net actuarial loss (2) 25,445 (9,669 ) 15,776 — — — — — — 15,776 Regulatory adjustment (3) 12,340 250 12,590 — — — — — — 12,590 Net current period other (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 1,771 — 1,771 337 Less: Translation adjustment — — — — — — 11 — 11 11 Net current period other (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 1,760 — 1,760 326 Ending Balance AOCI December 31, 2017 $ (61,520 ) $ 22,293 $ (39,227 ) $ (12,655 ) $ 4,809 $ (7,846 ) $ (609 ) $ — $ (609 ) $ (47,682 ) (1) The FSIRS reclassification amounts are included in the Net interest deductions line item on the Consolidated Statements of Income. Tax amounts related to FSIRS balances were estimated using a 38% effective rate. See also discussion above regarding the enactment of the TCJA. (2) These AOCI components are included in the computation of net periodic benefit cost (see Note 11 – Pension and Other Postretirement Benefits (3) The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in the Deferred charges and other assets line item on the Consolidated Balance Sheets). (4) Tax amounts related to existing before-tax before-tax |
Amount Recognized Before Income Tax in Accumulated Other Comprehensive Income | The following table represents amounts (before income tax impacts) included in Accumulated other comprehensive income (in the table above), that have not yet been recognized in net periodic benefit cost as of December 31, 2017 and 2016: Amounts Recognized in AOCI (Before Tax) (Thousands of dollars) 2017 2016 Net actuarial (loss) gain $ (448,555 ) $ (430,973 ) Prior service cost (4,368 ) (5,703 ) Less: amount recognized in regulatory assets 391,403 379,063 Recognized in AOCI $ (61,520 ) $ (57,613 ) |
Southwest Gas Corporation [Member] | |
Rollforward of Accumulated Other Comprehensive Income | The following table represents a rollforward of AOCI, presented on Southwest’s Consolidated Balance Sheets: AOCI—Rollforward (Thousands of dollars) Defined Benefit Plans (Note 11) FSIRS (Note 14) Before-Tax Tax After- Before- Tax After-Tax AOCI Beginning Balance AOCI December 31, 2016 $ (57,613 ) $ 21,893 $ (35,720 ) $ (15,999 ) $ 6,080 $ (9,919 ) $ (45,639 ) Net actuarial gain/(loss) (43,027 ) 10,326 (32,701 ) — — — (32,701 ) Other comprehensive income before reclassifications (43,027 ) 10,326 (32,701 ) — — — (32,701 ) FSIRS amounts reclassified from AOCI (5) — — — 3,344 (1,271 ) 2,073 2,073 Amortization of prior service cost (6) 1,335 (507 ) 828 — — — 828 Amortization of net actuarial loss (6) 25,445 (9,669 ) 15,776 — — — 15,776 Regulatory adjustment (7) 12,340 250 12,590 — — — 12,590 Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation (3,907 ) 400 (3,507 ) 3,344 (1,271 ) 2,073 (1,434 ) Ending Balance AOCI December 31, 2017 $ (61,520 ) $ 22,293 $ (39,227 ) $ (12,655 ) $ 4,809 $ (7,846 ) $ (47,073 ) (5) The FSIRS reclassification amounts are included in the Net interest deductions line item on the Consolidated Statements of Income. Tax amounts related to FSIRS balances were estimated using a 38% effective rate. See also discussion above regarding the enactment of the TCJA. (6) These AOCI components are included in the computation of net periodic benefit cost (see Note 11 – Pension and Other Postretirement Benefits (7) The regulatory adjustment represents the portion of the activity above that is expected to be recovered through rates in the future (the related regulatory asset is included in the Deferred charges and other assets line item on the Consolidated Balance Sheets). (8) Tax amounts related to existing before-tax before-tax |
Long-Term Debt (Tables)
Long-Term Debt (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Debt Disclosure [Abstract] | |
Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt | The Centuri secured revolving credit and term loan facility and Centuri other debt obligations (not actively traded) are categorized as Level 3, based on significant unobservable inputs to their fair values. Because Centuri’s debt is not publicly traded, fair values for the secured revolving credit and term loan facility and other debt obligations were based on a conventional discounted cash flow methodology and utilized current market pricing yield curves, across Centuri’s debt maturity spectrum, of other industrial bonds with an assumed credit rating comparable to the Company’s. December 31, 2017 December 31, 2016 Carrying Market Carrying Market (Thousands of dollars) Southwest Gas Corporation: Debentures: Notes, 4.45%, due 2020 $ 125,000 $ 129,273 $ 125,000 $ 129,703 Notes, 6.1%, due 2041 125,000 158,304 125,000 149,734 Notes, 3.875%, due 2022 250,000 256,163 250,000 254,900 Notes, 4.875%, due 2043 250,000 283,243 250,000 266,793 Notes, 3.8%, due 2046 300,000 302,970 300,000 283,029 8% Series, due 2026 75,000 96,063 75,000 94,691 Medium-term notes, 7.59% series, due 2017 — — 25,000 25,040 Medium-term notes, 7.78% series, due 2022 25,000 28,714 25,000 29,290 Medium-term notes, 7.92% series, due 2027 25,000 31,542 25,000 31,905 Medium-term notes, 6.76% series, due 2027 7,500 8,882 7,500 8,769 Unamortized discount and debt issuance costs (9,350 ) (9,931 ) 1,173,150 1,197,569 Revolving credit facility and commercial paper 150,000 150,000 5,000 5,000 Industrial development revenue bonds: Variable-rate bonds: Tax-exempt 50,000 50,000 50,000 50,000 2003 Series A, due 2038 50,000 50,000 50,000 50,000 2008 Series A, due 2038 50,000 50,000 50,000 50,000 2009 Series A, due 2039 50,000 50,000 50,000 50,000 Unamortized discount and debt issuance costs (2,119 ) (2,489 ) 197,881 197,511 Less: current maturities — (25,000 ) Long-term debt, less current maturities – Southwest Gas $ 1,521,031 $ 1,375,080 Centuri: Centuri term loan facility 199,578 207,588 $ 106,700 106,819 Unamortized debt issuance costs (1,111 ) (516 ) 198,467 106,184 Centuri secured revolving credit facility 56,472 56,525 41,185 41,292 Centuri other debt obligations 47,952 48,183 52,635 52,840 Less: current maturities (25,346 ) (25,101 ) Long-term debt, less current maturities – Centuri $ 277,545 $ 174,903 Consolidated Southwest Gas Holdings, Inc.: Southwest Gas Corporation long-term debt $ 1,521,031 $ 1,400,080 Centuri long-term debt 302,891 200,004 Less: current maturities (25,346 ) (50,101 ) Long-term debt, less current maturities – Southwest Gas Holdings, Inc. $ 1,798,576 $ 1,549,983 |
Summary of Effective Interest Rates on Variable-Rate IDRBs | The effective interest rates on Southwest’s variable-rate IDRBs are included in the table below: December 31, 2017 December 31, 2016 2003 Series A 2.44 % 1.47 % 2008 Series A 2.59 % 1.53 % 2009 Series A 2.40 % 1.43 % Tax-exempt 2.56 % 1.51 % |
Estimated Maturities of Long-Term Debt | Estimated maturities of long-term debt for the next five years are (in thousands): Southwest Centuri Total 2018 $ — $ 25,346 $ 25,346 2019 — 26,707 26,707 2020 125,000 27,955 152,955 2021 — 25,140 25,140 2022 425,000 194,577 619,577 |
Pension and Other Postretirem35
Pension and Other Postretirement Benefits (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Retirement Benefits [Abstract] | |
Cost of Retirement Plan | The cost of the plan is disclosed below (in thousands): 2017 2016 2015 Employee Investment Plan cost $ 5,112 $ 4,976 $ 5,072 |
Schedule of Assumptions Used | The rates are presented in the table below: December 31, 2017 December 31, 2016 Discount rate 3.75 % 4.50 % Weighted-average rate of compensation increase 3.25 % 3.25 % Asset return assumption 7.00 % 7.00 % |
Schedule of Amounts Recognized in Balance Sheet and Income Statement | The following table sets forth the retirement plan, SERP, and PBOP funded statuses and amounts recognized on the Consolidated Balance Sheets and Consolidated Statements of Income. 2017 2016 Qualified SERP PBOP Qualified SERP PBOP (Thousands of dollars) Change in benefit obligations Benefit obligation for service rendered to date at beginning of year (PBO/PBO/APBO) $ 1,048,353 $ 43,311 $ 73,865 $ 1,044,817 $ 42,720 $ 72,632 Service cost 23,392 309 1,468 22,833 331 1,499 Interest cost 46,083 1,883 3,232 46,027 1,859 3,180 Actuarial loss (gain) 133,017 3,334 (71 ) 8,550 1,347 (2,060 ) Benefits paid (47,361 ) (3,110 ) (3,172 ) (73,874 ) (2,946 ) (1,386 ) Benefit obligation at end of year (PBO/PBO/APBO) 1,203,484 45,727 75,322 1,048,353 43,311 73,865 Change in plan assets Market value of plan assets at beginning of year 738,962 — 48,113 736,880 — 43,584 Actual return on plan assets 144,064 — 7,742 39,956 — 4,818 Employer contributions 36,000 3,110 — 36,000 2,946 — Benefits paid (47,361 ) (3,110 ) (1,247 ) (73,874 ) (2,946 ) (289 ) Market value of plan assets at end of year 871,665 — 54,608 738,962 — 48,113 Funded status at year end $ (331,819 ) $ (45,727 ) $ (20,714 ) $ (309,391 ) $ (43,311 ) $ (25,752 ) Weighted-average assumptions (benefit obligation) Discount rate 3.75 % 3.75 % 3.75 % 4.50 % 4.50 % 4.50 % Weighted-average rate of compensation increase 3.25 % 3.25 % N/A 3.25 % 3.25 % N/A |
Schedule of Accumulated Benefit Obligation | The accumulated benefit obligation for the retirement plan and the SERP is presented below (in thousands): December 31, 2017 December 31, 2016 Retirement plan $ 1,088,203 $ 939,002 SERP 44,343 40,852 |
Schedule of Expected Benefit Payments | Benefits expected to be paid for pension, SERP, and PBOP over the next 10 years are as follows (in millions): 2018 2019 2020 2021 2022 2023-2027 Pension $ 51.0 $ 52.2 $ 53.6 $ 55.1 $ 56.6 $ 308.3 SERP 3.0 3.0 3.0 2.9 2.9 14.1 PBOP 4.1 4.2 4.3 4.3 4.2 19.6 |
Schedule of Net Periodic Benefit Cost and Weighted-Average Assumptions | Components of net periodic benefit cost Qualified Retirement Plan SERP PBOP 2017 2016 2015 2017 2016 2015 2017 2016 2015 (Thousands of dollars) Service cost $ 23,392 $ 22,833 $ 25,123 $ 309 $ 331 $ 320 $ 1,468 $ 1,499 $ 1,641 Interest cost 46,083 46,027 44,229 1,883 1,859 1,695 3,232 3,180 2,999 Expected return on plan assets (55,196 ) (56,558 ) (57,808 ) — — — (3,358 ) (3,149 ) (3,464 ) Amortization of prior service cost — — — — — — 1,335 1,335 1,335 Amortization of net actuarial loss 24,004 25,266 32,743 1,441 1,383 1,293 — 417 345 Net periodic benefit cost $ 38,283 $ 37,568 $ 44,287 $ 3,633 $ 3,573 $ 3,308 $ 2,677 $ 3,282 $ 2,856 Weighted-average Discount rate 4.50 % 4.50 % 4.25 % 4.50 % 4.50 % 4.25 % 4.50 % 4.50 % 4.25 % Expected return on plan assets 7.00 % 7.25 % 7.75 % N/A N/A N/A 7.00 % 7.25 % 7.75 % Weighted-average rate of compensation increase 3.25 % 3.25 % 2.75 % 3.25 % 3.25 % 2.75 % N/A N/A N/A |
Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in Net Periodic Benefit Cost and Other Comprehensive Income | Other Changes in Plan Assets and Benefit Obligations Recognized in Net Periodic Benefit Cost and Other Comprehensive Income 2017 2016 2015 Total Qualified SERP PBOP Total Qualified SERP PBOP Total Qualified SERP PBOP (Thousands of dollars) Net actuarial loss (gain) (a) $ 43,027 $ 44,149 $ 3,334 $ (4,456 ) $ 22,770 $ 25,153 $ 1,347 $ (3,730 ) $ 30,519 $ 26,949 $ 2,322 $ 1,248 Amortization of prior (1,335 ) — — (1,335 ) (1,335 ) — — (1,335 ) (1,335 ) — — (1,335 ) Amortization of net (25,445 ) (24,004 ) (1,441 ) — (27,066 ) (25,266 ) (1,383 ) (417 ) (34,381 ) (32,743 ) (1,293 ) (345 ) Regulatory adjustment (12,340 ) (18,131 ) — 5,791 5,584 102 — 5,482 5,646 5,214 — 432 Recognized in other comprehensive (income) loss 3,907 2,014 1,893 — (47 ) (11 ) (36 ) — 449 (580 ) 1,029 — Net periodic benefit costs recognized in net income 44,593 38,283 3,633 2,677 44,423 37,568 3,573 3,282 50,451 44,287 3,308 2,856 Total of amount $ 48,500 $ 40,297 $ 5,526 $ 2,677 $ 44,376 $ 37,557 $ 3,537 $ 3,282 $ 50,900 $ 43,707 $ 4,337 $ 2,856 |
Schedule of Fair Value of Plan Assets | The following table sets forth, by level within the three-level fair value hierarchy, the fair values of the assets of the qualified pension plan and the PBOP as of December 31, 2017 and December 31, 2016. The SERP has no assets. December 31, 2017 December 31, 2016 Qualified PBOP Total Qualified PBOP Total Assets at fair value (thousands of dollars): Level 1 – Quoted prices in active markets for identical financial assets Mutual funds $ — $ 27,020 $ 27,020 $ — $ 24,922 $ 24,922 Total Level 1 Assets (1) $ — $ 27,020 $ 27,020 $ — $ 24,922 $ 24,922 Level 2 – Significant other observable inputs Private commingled equity funds (2) International $ 340,217 $ 10,577 $ 350,794 $ 290,668 $ 9,140 $ 299,808 Large and medium capitalization 136,982 4,258 141,240 121,434 3,819 125,253 Small capitalization 28,955 900 29,855 25,947 816 26,763 Emerging markets 56,259 1,749 58,008 45,309 1,424 46,733 Private commingled fixed income funds (3) U.S. corporate bonds 157,460 4,895 162,355 161,086 5,066 166,152 U.S. debt market long duration 59,986 1,865 61,851 77,349 2,432 79,781 U.S. Treasury securities 83,771 2,604 86,375 8,665 272 8,937 Pooled funds and mutual funds 4,676 735 5,411 4,889 216 5,105 Government fixed income and mortgage backed securities 172 5 177 167 5 172 Total Level 2 assets (4) $ 868,478 $ 27,588 $ 896,066 $ 735,514 $ 23,190 $ 758,704 Total Plan assets at fair value $ 868,478 $ 54,608 $ 923,086 $ 735,514 $ 48,112 $ 783,626 Insurance company general account contracts (5) 3,187 — 3,187 3,448 — 3,448 Total Plan assets $ 871,665 $ 54,608 $ 926,273 $ 738,962 $ 48,112 $ 787,074 (1) The Mutual funds category above is an intermediate-term bond fund whose manager employs multiple concurrent strategies and takes only moderate risk in each, thereby reducing the risk of poor performance arising from any single source, and a balanced fund that invests in a diversified portfolio of common stocks, preferred stocks and fixed-income securities. Strategies utilized by the bond fund include duration management, yield curve or maturity structuring, sector rotation, and all bottom-up in-house (2) The private commingled equity funds include common collective trusts that invest in a diversified portfolio of domestic and international securities regularly traded on securities exchanges. These funds are shown in the above table at net asset value (“NAV”), which is the value of securities in the fund less the amount of any liabilities outstanding. Investment strategies employed by the funds include: • Domestic equities • International developed countries equities • Emerging markets equities Shares in the private equity commingled funds may be redeemed given one business day notice. While they are private equity funds and reported at NAV, due to the short redemption notice period, the lack of significant redemption fees, the fact that the underlying investments are exchange-traded, and that substantial liabilities do not exist subject to the NAV calculation, these investments are viewed as indirectly observable (level 2) and are also therefore, not excluded from the body of the fair value table as a reconciling item. Two funds are classified as international funds. One invests in international financial markets, primarily those of developed economies in Europe and the Pacific Basin. The fund invests primarily in equity securities issued by foreign corporations, but may invest in other securities perceived as offering attractive investment return opportunities. The other provides diversified exposure to global equity markets. The fund seeks to provide long-term capital growth by investing primarily in securities listed on the major developed equity markets of the United States, Europe, and Asia, as well as within those listed on emerging country equity markets on a tactical basis. The large and medium capitalization fund is designed to track the performance of the large and medium capitalization companies contained in the index, which represents approximately 90% of the market capitalization of the United States stock market. The small capitalization fund is designed to provide maximum long-term appreciation through investments that are well diversified by industry. The emerging markets fund was developed to invest in emerging market equities worldwide. The purposes of the fund’s operations, “emerging market countries” include every country in the world except the developed markets of the United States, Canada, Japan, Australia, New Zealand, Hong Kong and Singapore, and most countries located in Western Europe. Fund investments are made directly in each country or, where direct investment is inefficient or prohibited, through appropriate financial instruments or participation in commingled funds. (3) The private commingled fixed income funds include domestic fixed income securities. These funds are shown in the above table at NAV. Shares in the private commingled fixed equity funds may be redeemed given one business day notice. While they are private equity funds and reported at NAV, due to the short redemption notice period, the lack of significant redemption fees, the fact that the underlying investments are exchange-traded, and that substantial liabilities do not exist subject to the NAV calculation, these investments are viewed as indirectly observable (level 2) and are also therefore, not excluded from the body of the fair value table as a reconciling item. The U.S. corporate bond fund seeks to provide high quality, mostly corporate bond-based exposure to fixed income securities which closely match those found in discount curves used to value United States pension liabilities. The United States debt market long duration fund provides participation in the full spectrum of investment opportunities in primarily United States debt markets with longer maturities. The fund seeks to offer effective diversification against equities, take advantage of market trading opportunities, and provide a competitive rate of return on assets. The fund’s current duration is close to 14 years. The United States Treasuries securities fund seeks to replicate the risk and return characteristics of the Barclays Treasury U.S. Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) 28-29 (4) With the exception of items (2) and (3), which are discussed in detail above, the Level 2 assets consist mainly of pooled funds and mutual funds. These funds are collective short-term funds that invest in Treasury bills and money market funds and are used as a temporary cash repository. (5) The insurance company general account contracts are annuity insurance contracts used to pay the pensions of employees who retired prior to 1989. The balance of the account disclosed in the above table is the contract value, which is the result of deposits, withdrawals, and interest credits. |
Stock-Based Compensation (Table
Stock-Based Compensation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |
Schedule of Stock-Based Plan Compensation Expense, Including Cash Award | The table below shows total stock-based plan compensation expense, including the cash award, which was recognized in the Consolidated Statements of Income (in thousands): 2017 2016 2015 Stock-based compensation plan expense, net of related tax benefits $ 6,751 $ 7,185 $ 7,278 Stock-based compensation plan related tax benefits 4,137 4,404 4,461 |
Schedule of Stock Options Activity | The following tables summarize the stock option plan activity and related information (thousands of options): 2017 2016 2015 Number Weighted- Number of Weighted- Number of Weighted- Outstanding at the beginning of the year — N/A 17 $ 31.64 36 $ 28.97 Exercised during the year — — (17 ) 31.64 (19 ) 26.69 Forfeited or expired during the year — — — — — — Outstanding and exercisable at year end — N/A — N/A 17 $ 31.64 |
Schedule of Aggregate Intrinsic Value of Outstanding and Exercisable Options | The aggregate intrinsic value of outstanding and exercisable options, and options that were exercised, are presented in the table below (in thousands): 2017 2016 2015 Outstanding and exercisable $ — $ — $ 394 Exercised — 554 590 |
Summary of Market Prices of Common Stock | The aggregate intrinsic value of outstanding and exercisable options, and options that were exercised, are presented in the table below (in thousands): 2017 2016 2015 Outstanding and exercisable $ — $ — $ 394 Exercised — 554 590 December 31, 2017 December 31, 2016 December 31, 2015 Market value of Company stock $ 80.48 $ 76.62 $ 55.16 |
Schedule of Nonvested Performance and Restricted Stock Unit Plans | The following table summarizes the activity of the management incentive plan shares and restricted stock/units as of December 31, 2017 (thousands of shares): Management Weighted- Restricted Weighted- Nonvested/unissued at beginning of year 168 $ 55.62 262 $ 46.41 Granted 32 85.44 106 85.39 Dividends 3 7 Forfeited or expired (1 ) 59.02 (1 ) 69.85 Vested and issued (2) (75 ) 51.93 (69 ) 53.28 Nonvested/unissued at December 31, 2017 127 $ 63.98 305 $ 57.41 (1) The number of securities granted includes 33,000 performance shares, which was derived by assuming that target performance will be achieved during the relevant performance period. (2) Includes shares for retiree payouts and those converted for taxes. |
Income Taxes (Tables)
Income Taxes (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Summary of Income Before Taxes and Noncontrolling Interest for Domestic and Foreign Operations | The following is a summary of income before taxes and noncontrolling interest for domestic and foreign operations (thousands of dollars): Year ended December 31, 2017 2016 2015 U.S. $ 246,131 $ 218,810 $ 221,660 Foreign 12,899 12,713 (2,328 ) Total income before income taxes $ 259,030 $ 231,523 $ 219,332 |
Summary of Income Tax Expense (Benefit) | Income tax expense (benefit) consists of the following (thousands of dollars): Year Ended December 31, 2017 2016 2015 Current: Federal $ (1,316 ) $ 541 $ 21,321 State 2,965 5,748 9,899 Foreign 5,203 4,298 650 6,852 10,587 31,870 Deferred: Federal 58,443 68,270 51,132 State 1,837 140 (2,574 ) Foreign (2,044 ) (529 ) (526 ) 58,236 67,881 48,032 Total income tax expense $ 65,088 $ 78,468 $ 79,902 |
Significant Components of Deferred Income Tax Expense (Benefit) | Deferred income tax expense (benefit) consists of the following significant components (thousands of dollars): Year Ended December 31, 2017 2016 2015 Deferred federal and state: Property-related items $ 44,516 $ 76,217 $ 65,931 Purchased gas cost adjustments 8,500 361 (32,993 ) Employee benefits (2,517 ) (1,327 ) 623 Regulatory Adjustments 14,401 6,322 1,545 All other deferred (5,935 ) (12,854 ) 13,787 Total deferred federal and state 58,965 68,719 48,893 Deferred ITC, net (729 ) (838 ) (861 ) Total deferred income tax expense $ 58,236 $ 67,881 $ 48,032 |
Reconciliation of U.S Federal Statutory Rate to Consolidated Effective Tax Rate | A reconciliation of the U.S. federal statutory rate to the consolidated effective tax rate for 2017, 2016, and 2015 (and the sources of these differences and the effect of each) are summarized as follows: Year Ended December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.0 % 35.0 % 35.0 % Net state taxes 1.1 1.4 1.8 Property-related items — — 0.1 Tax credits (0.4 ) (0.4 ) (0.4 ) Company owned life insurance (1.6 ) (1.2 ) 0.1 Change in U.S. Federal Income Tax Rate (7.8 ) — — All other differences (1.2 ) (0.9 ) (0.2 ) Consolidated effective income tax rate 25.1 % 33.9 % 36.4 % |
Deferred Tax Assets and Liabilities | Deferred tax assets and liabilities consist of the following (thousands of dollars): December 31, 2017 2016 Deferred tax assets: Deferred income taxes for future amortization of ITC and excess deferred taxes $ 98,912 $ 1,094 Employee benefits 31,323 38,231 Alternative minimum tax credit 4,390 4,827 Net operating losses and credits 11,460 1,204 Interest rate swap 3,037 6,080 Other 13,870 18,415 Valuation allowance (728 ) (495 ) 162,264 69,356 Deferred tax liabilities: Property-related items, including accelerated depreciation 598,371 872,136 Regulatory balancing accounts 6,067 1,104 Unamortized ITC 981 1,710 Debt-related costs 3,380 5,712 Intangibles 7,656 8,803 Other 21,289 19,256 637,744 908,721 Net noncurrent deferred tax liabilities $ 475,480 $ 839,365 |
Reconciliation of Unrecognized Tax Benefits | A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (thousands of dollars): 2017 2016 Unrecognized tax benefits at beginning of year $ 1,231 $ 296 Gross increases – tax positions in prior period 100 897 Gross decreases – tax positions in prior period — — Gross increases – current period tax positions 99 38 Gross decreases – current period tax positions — — Settlements — — Lapse in statute of limitations — — Unrecognized tax benefits at end of year $ 1,430 $ 1,231 |
Southwest Gas Corporation [Member] | |
Summary of Income Tax Expense (Benefit) | Income tax expense (benefit) consists of the following (thousands of dollars): Year Ended December 31, 2017 2016 2015 Current: Federal $ 318 $ (9,695 ) $ 3,789 State 1,420 2,510 6,229 1,738 (7,185 ) 10,018 Deferred: Federal 60,662 66,037 53,657 State 735 (268 ) (2,320 ) 61,397 65,769 51,337 Total income tax expense from continuing operations 63,135 58,584 61,355 Discontinued operations — 19,884 18,547 Total income tax expense $ 63,135 $ 78,468 $ 79,902 |
Significant Components of Deferred Income Tax Expense (Benefit) | Deferred income tax expense (benefit) consists of the following significant components (thousands of dollars): Year Ended December 31, 2017 2016 2015 Deferred federal and state: Property-related items $ 49,129 $ 72,811 $ 68,105 Purchased gas cost adjustments 8,500 361 (32,993 ) Employee benefits (5,707 ) (139 ) (4,795 ) Regulatory Adjustments 14,401 6,322 1,545 All other deferred (4,197 ) (12,748 ) 20,336 Total deferred federal and state 62,126 66,607 52,198 Deferred ITC, net (729 ) (838 ) (861 ) Total deferred income tax expense $ 61,397 $ 65,769 $ 51,337 |
Reconciliation of U.S Federal Statutory Rate to Consolidated Effective Tax Rate | A reconciliation of the U.S. federal statutory rate to the consolidated effective tax rate for 2017, 2016, and 2015 (and the sources of these differences and the effect of each) are summarized as follows: Year Ended December 31, 2017 2016 2015 U.S. federal statutory income tax rate 35.0 % 35.0 % 35.0 % Net state taxes 0.6 0.8 1.0 Property-related items — — 0.1 Tax credits (0.4 ) (0.5 ) (0.5 ) Company owned life insurance (1.7 ) (1.5 ) — Change in U.S. Federal Income Tax Rate (3.6 ) — — All other differences (1.2 ) (0.9 ) (0.1 ) Effective income tax rate from continuing operations 28.7 % 32.9 % 35.5 % |
Deferred Tax Assets and Liabilities | Deferred tax assets and liabilities consist of the following (thousands of dollars): December 31, 2017 2016 Deferred tax assets: Deferred income taxes for future amortization of ITC and excess deferred taxes $ 98,912 $ 1,094 Employee benefits 18,707 22,426 Alternative minimum tax credit 4,390 4,827 Net operating losses and credits 10,070 — Interest rate swap 3,037 6,080 Other 8,820 15,204 Valuation allowance (58 ) (223 ) 143,878 49,408 Deferred tax liabilities: Property-related items, including accelerated depreciation 561,493 830,758 Regulatory balancing accounts 6,067 1,104 Unamortized ITC 981 1,710 Debt-related costs 3,380 5,712 Other 17,200 16,233 589,121 855,517 Net deferred tax liabilities before discontinued operations 445,243 806,109 Discontinued operations — 33,256 Net deferred tax liabilities $ 445,243 $ 839,365 |
Reconciliation of Unrecognized Tax Benefits | A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (thousands of dollars): 2017 2016 Unrecognized tax benefits at beginning of year $ 903 $ — Gross increases – tax positions in prior period 67 865 Gross decreases – tax positions in prior period — — Gross increases – current period tax positions 99 38 Gross decreases – current period tax positions — — Settlements — — Lapse in statute of limitations — — Unrecognized tax benefits at end of year $ 1,069 $ 903 |
Summary of Income Before Taxes for Continuing and Discontinued Operations | The following is a summary of income before taxes for continuing and discontinued operations (refer to Note 1 – Summary of Significant Accounting Policies ) (thousands of dollars): Year ended December 31, 2017 2016 2015 Income from continuing operations before income taxes $ 219,953 $ 178,007 $ 172,980 Income from discontinued operations before income taxes — 53,516 46,352 Total income before income taxes $ 219,953 $ 231,523 $ 219,332 |
Derivatives and Fair Value Me38
Derivatives and Fair Value Measurements (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Fair Value Disclosures [Abstract] | |
Notional Amounts under Swaps Contracts | The differential is calculated based on the notional amounts under the contracts, which are detailed in the table below (thousands of dekatherms): December 31, 2017 December 31, 2016 Contract notional amounts 10,929 10,543 |
Amount of Gain or Losses Recognized in Income on Derivatives | The following table sets forth the gains and (losses) recognized on Southwest’s Swaps (derivatives) for the years ended December 31, 2017, 2016, and 2015 and their location in the Consolidated Statements of Income: Instrument Location of Gain or (Loss) 2017 2016 2015 Swaps Net cost of gas sold $ (11,572 ) $ 5,006 $ (7,598 ) Swaps Net cost of gas sold 11,572 * (5,006 )* 7,598 * Total $ — $ — $ — * Represents the impact of regulatory deferral accounting treatment under U.S. GAAP for rate-regulated entities. |
Fair Values of Swaps in Consolidated Balance Sheets | The following table sets forth the fair values of the Swaps and their location in the Consolidated Balance Sheets of Southwest and the Company (thousands of dollars): Fair values of derivatives not designated as hedging instruments: December 31, 2017 Instrument Balance Sheet Location Asset Liability Net Swaps Other current liabilities $ 11 $ (4,468 ) $ (4,457 ) Swaps Other deferred credits 19 (1,342 ) (1,323 ) Total $ 30 $ (5,810 ) $ (5,780 ) December 31, 2016 Balance Sheet Location Asset Liability Net Swaps Deferred charges and other assets $ 899 $ (54 ) $ 845 Swaps Prepaids and other current assets 3,551 (19 ) 3,532 Total $ 4,450 $ (73 ) $ 4,377 |
Paid to and Received from Counterparties for Settlements of Matured Swaps | The following table presents the amounts paid to and received from counterparties for settlements of matured Swaps. Year ended Year ended Year ended (Thousands of dollars) Paid to counterparties $ 3,100 $ 5,583 $ 7,537 Received from counterparties $ 1,685 $ 726 $ — |
Regulatory Assets/Liabilities Offsetting Derivatives at Fair Value in Condensed Consolidated Balance Sheets | The following table details the regulatory assets/(liabilities) offsetting the derivatives at fair value in the Consolidated Balance Sheets (thousands of dollars). December 31, 2017 Instrument Balance Sheet Location Net Total Swaps Prepaids and other current assets $ 4,457 Swaps Deferred charges and other assets 1,323 December 31, 2016 Instrument Balance Sheet Location Net Total Swaps Other deferred credits $ (845 ) Swaps Other current liabilities (3,532 ) |
Summary of Financial Assets and Liabilities at Fair Value | The following table sets forth, by level within the three-level fair value hierarchy that ranks the inputs used to measure fair value by their reliability, financial assets and liabilities that were accounted for at fair value (see Note 11 – Pension and Other Post Retirement Benefits for definitions of the levels of the fair value hierarchy): Level 2 – Significant other observable inputs December 31, 2017 December 31, 2016 (Thousands of dollars) Assets at fair value: Prepaids and other current assets – Swaps $ — $ 3,532 Deferred charges and other assets – Swaps — 845 Liabilities at fair value: Other current liabilities – Swaps (4,457 ) — Other deferred credits – Swaps (1,323 ) — Net Assets (Liabilities) $ (5,780 ) $ 4,377 |
Segment Information (Tables)
Segment Information (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Segment Reporting [Abstract] | |
Accounts Receivable for Services | Accounts receivable for these services, which are not eliminated during consolidation, are presented in the table below (in thousands). December 31, 2017 December 31, 2016 Accounts receivable for Centuri services $ 12,987 $ 10,585 |
Schedule of Revenues by Geographic Area | The following table presents the amount of revenues for both segments by geographic area (thousands of dollars): December 31, December 31, December 31, Revenues (a) United States $ 2,345,134 $ 2,256,600 $ 2,289,133 Canada 203,658 203,890 174,492 Total $ 2,548,792 $ 2,460,490 $ 2,463,625 (a) Revenues are attributed to countries based on the location of customers. |
Schedule of Segment Reporting Information | The financial information pertaining to the natural gas operations and construction services segments for each of the three years in the period ended December 31, 2017 is as follows (thousands of dollars): 2017 Gas Construction Other Total Revenues from unaffiliated customers $ 1,302,308 $ 1,149,325 $ — $ 2,451,633 Intersegment sales — 97,159 — 97,159 Total $ 1,302,308 $ 1,246,484 $ — $ 2,548,792 Interest revenue $ 2,784 $ 3 $ — $ 2,787 Interest expense $ 69,733 $ 7,986 $ 345 $ 78,064 Depreciation and amortization $ 201,922 $ 49,029 $ — $ 250,951 Income tax expense $ 63,135 $ 2,390 $ (437 ) $ 65,088 Segment net income $ 156,818 $ 38,360 $ (1,337 ) $ 193,841 Segment assets $ 5,482,669 $ 752,496 $ 1,901 $ 6,237,066 Capital expenditures $ 560,448 $ 63,201 $ — $ 623,649 2016 Gas Construction Other Total Revenues from unaffiliated customers $ 1,321,412 $ 1,040,957 $ — $ 2,362,369 Intersegment sales — 98,121 — 98,121 Total $ 1,321,412 $ 1,139,078 $ — $ 2,460,490 Interest revenue $ 1,848 $ 1 $ — $ 1,849 Interest expense $ 66,997 $ 6,663 $ — $ 73,660 Depreciation and amortization $ 233,463 $ 55,669 $ — $ 289,132 Income tax expense $ 58,584 $ 19,884 $ — $ 78,468 Segment net income $ 119,423 $ 32,618 $ — $ 152,041 Segment assets $ 5,001,756 $ 579,370 $ — $ 5,581,126 Capital expenditures $ 457,120 $ 72,411 $ — $ 529,531 2015 Gas Construction Other Total Revenues from unaffiliated customers $ 1,454,639 $ 904,870 $ — $ 2,359,509 Intersegment sales — 104,116 — 104,116 Total $ 1,454,639 $ 1,008,986 $ — $ 2,463,625 Interest revenue $ 1,754 $ 419 $ — $ 2,173 Interest expense $ 64,095 $ 7,784 $ — $ 71,879 Depreciation and amortization $ 213,455 $ 56,656 $ — $ 270,111 Income tax expense $ 61,355 $ 18,547 $ — $ 79,902 Segment net income $ 111,625 $ 26,692 $ — $ 138,317 Segment assets $ 4,822,845 $ 535,840 $ — $ 5,358,685 Capital expenditures $ 438,289 $ 49,711 $ — $ 488,000 |
Quarterly Financial Data (Table
Quarterly Financial Data (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Quarterly Financial Information Disclosure [Abstract] | |
Schedule of Quarterly Financial Information | Quarter Ended March 31 June 30 September 30 December 31 (Thousands of dollars, except per share amounts) 2017 Southwest Gas Holdings, Inc.: Operating revenues $ 654,737 $ 560,469 $ 593,153 $ 740,433 Operating income 119,492 43,408 30,132 130,668 Net income 69,005 18,121 10,420 96,396 Net income attributable to Southwest Gas Holdings, Inc. 69,308 17,864 10,204 96,465 Basic earnings per common share (1) 1.46 0.38 0.21 2.00 Diluted earnings per common share (1) 1.45 0.37 0.21 2.00 Southwest Gas Corporation: Operating revenues $ 462,602 $ 260,162 $ 213,059 $ 366,485 Operating income 131,067 27,489 5,065 113,029 Net income (loss) 76,938 9,522 (4,024 ) 74,382 2016 Southwest Gas Holdings, Inc.: (2) Operating revenues $ 731,248 $ 547,748 $ 539,969 $ 641,525 Operating income 134,096 28,116 15,539 117,963 Net income 75,355 9,099 2,907 65,694 Net income attributable to Southwest Gas Holdings, Inc. 75,446 8,943 2,472 65,180 Basic earnings per common share (1) 1.59 0.19 0.05 1.37 Diluted earnings per common share (1) 1.58 0.19 0.05 1.36 Southwest Gas Corporation: (2) (3) Operating revenues Continuing operations $ 525,100 $ 255,648 $ 200,179 $ 340,485 Discontinued operations – construction services 206,148 292,100 339,790 301,040 Total $ 731,248 $ 547,748 $ 539,969 $ 641,525 Operating income (loss) Continuing operations $ 135,945 $ 15,269 $ (10,231 ) $ 95,745 Discontinued operations – construction services (1,849 ) 12,847 25,770 22,218 Total $ 134,096 $ 28,116 $ 15,539 $ 117,963 Net income (loss) Continuing operations $ 77,583 $ 2,358 $ (12,405 ) $ 51,887 Discontinued operations – construction services (2,137 ) 6,585 14,877 13,293 Total $ 75,446 $ 8,943 $ 2,472 $ 65,180 Quarter Ended March 31 June 30 September 30 December 31 2015 Southwest Gas Holdings, Inc.: (2) Operating revenues $ 734,220 $ 538,604 $ 505,396 $ 685,405 Operating income 129,556 25,047 16,143 117,586 Net income (loss) 71,879 5,063 (4,210 ) 66,698 Net income attributable to Southwest Gas Holdings, Inc. 71,983 4,949 (4,734 ) 66,119 Basic earnings per common share (1) 1.54 0.11 (0.10 ) 1.40 Diluted earnings per common share (1) 1.53 0.10 (0.10 ) 1.38 Southwest Gas Corporation: (2) (3) Operating revenues Continuing operations $ 553,115 $ 286,643 $ 219,420 $ 395,461 Discontinued operations – construction services 181,105 251,961 285,976 289,944 Total $ 734,220 $ 538,604 $ 505,396 $ 685,405 Operating income (loss) Continuing operations $ 137,171 $ 12,958 $ (9,274 ) $ 93,928 Discontinued operations – construction services (7,615 ) 12,089 25,417 23,658 Total $ 129,556 $ 25,047 $ 16,143 $ 117,586 Net income (loss) Continuing operations $ 78,921 $ (657 ) $ (18,939 ) $ 52,300 Discontinued operations – construction services (6,938 ) 5,606 14,205 13,819 Total $ 71,983 $ 4,949 $ (4,734 ) $ 66,119 (1) The sum of quarterly earnings (loss) per average common share may not equal the annual earnings (loss) per share due to the ongoing change in the weighted-average number of common shares. (2) Refer to Notes 1 and 18. Effective 2017, Southwest Gas Holdings, Inc. (“Company) is the successor equity issuer to Southwest Gas Corporation (“Southwest”). Both Southwest and Centuri became subsidiaries of the Company. (3) Periods prior to 2017 depict Centuri amounts as discontinued operations of Southwest. |
Construction Services Noncont41
Construction Services Noncontrolling Interests (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Noncontrolling Interest [Abstract] | |
Summary of Redeemable Noncontrolling Interest | The following depicts changes to the balance of the redeemable noncontrolling interest between the indicated periods. Redeemable (Thousands of dollars): Balance, December 31, 2016 $ 22,590 Net Income (loss) attributable to redeemable noncontrolling interest 248 Foreign currency exchange translation adjustment 11 Centuri distribution to redeemable noncontrolling interest (204 ) Adjustment to redemption value 355 Redemption of Centuri shares from noncontrolling parties (23,000 ) Balance, December 31, 2017 $ — |
Reorganization Impacts - Disc42
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Restructuring and Related Activities [Abstract] | |
Summary of Discontinued Operations - Construction Services in Condensed Consolidated Balance Sheet and Condensed Consolidated Income Statements | The following table presents the major categories of assets and liabilities within the amounts reported as discontinued operations – construction services in the Consolidated Balance Sheet of Southwest Gas Corporation: December 31, 2016 (Thousands of dollars) Assets: Other property and investments $ 233,774 Cash and cash equivalents 9,042 Accounts receivable, net of allowances 173,300 Prepaids and other current assets 10,470 Goodwill 129,888 Other noncurrent assets 22,897 Discontinued operations – construction services – assets $ 579,371 Liabilities: Current maturities of long-term debt $ 25,101 Accounts payable 46,440 Other current liabilities 74,518 Long-term debt, less current maturities 174,903 Deferred income taxes and other deferred credits 59,653 Discontinued operations – construction services – liabilities $ 380,615 The following table presents the components of the Discontinued operations – construction services non-owner December 31, 2016 (Thousands of dollars) Construction services equity $ (4,390 ) Construction services noncontrolling interest (2,217 ) Construction services redeemable noncontrolling interest 22,590 Discontinued operations – construction services non-owner $ 15,983 The following table presents the major income statement components of discontinued operations – construction services reported in the Consolidated Income Statements of Southwest Gas Corporation: Results of Construction Services Year Ended December 31, 2016 2015 (Thousands of dollars) Construction revenues $ 1,139,078 $ 1,008,986 Operating expenses: Construction expenses 1,024,423 898,781 Depreciation and amortization 55,669 56,656 Operating income 58,986 53,549 Other income (deductions) 1,193 587 Net interest deductions 6,663 7,784 Income before income taxes 53,516 46,352 Income tax expense 19,884 18,547 Net income 33,632 27,805 Net income attributable to noncontrolling interests 1,014 1,113 Discontinued operations – construction services – net income $ 32,618 $ 26,692 |
Acquisition of Construction S43
Acquisition of Construction Services Business (Tables) | 12 Months Ended |
Dec. 31, 2017 | |
Business Combinations [Abstract] | |
Summary of Preliminary Estimated Fair Values of Assets Acquired and Liabilities Assumed | The preliminary estimated fair values of assets acquired and liabilities assumed as of November 1, 2017, are as follows (in millions of dollars): Cash and cash equivalents $ 0.8 Contracts receivable 18.3 Other receivables 5.4 Property, plant and equipment 15.1 Prepaid expenses and deposits 1.7 Intangible assets 44.8 Goodwill 32.0 Total assets acquired 118.1 Current liabilities (18.5 ) Other long-term liabilities (0.3 ) Net assets acquired $ 99.3 |
Summary of Estimated Future Amortization of Intangible Assets Acquired | The estimated future amortization of the intangible assets acquired in the acquisition for the next five years is as follows (in thousands): 2018 $ 3,641 2019 3,724 2020 3,669 2021 3,391 2022 3,391 |
Schedule of Pro Forma Consolidated Financial Information | The unaudited pro forma consolidated financial information for fiscal 2017 and fiscal 2016 (assuming the acquisition of Neuco occurred as of the beginning fiscal 2016) is as follows (in thousands of dollars, except per share amounts): Year Ended December 31, 2017 2016 Total operating revenues $ 2,639,452 $ 2,556,124 Net income attributable to Southwest Gas Holdings, Inc. $ 203,245 $ 156,108 Basic earnings per share $ 4.24 $ 3.29 Diluted earnings per share $ 4.24 $ 3.26 |
Schedule of Statements of Income Operations | Actual results from Neuco operations, excluding deal costs incurred by Centuri, included in the Consolidated Statements of Income since the date of acquisition are as follows (in thousands of dollars): Year ended Construction revenues $ 17,182 Net income attributable to Neuco 2,772 |
Summary of Significant Accoun44
Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) | Jul. 30, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Aug. 31, 2017 |
Significant Accounting Policies [Line Items] | ||||||
Acquisition adjustments net | $ 196,000 | |||||
Prepaid and other current assets | $ 40,000,000 | $ 953,000 | ||||
Corporate federal income tax rate | 35.00% | 35.00% | 35.00% | |||
Loss carry forwards limitations on use | 80% of taxable income, with the ability to indefinitely carryforward unutilized NOLs to reduce future taxable income | |||||
Reductions in accumulated deferred income tax | $ 8,000,000 | |||||
Non-cash construction advances - non-cash investing item | 3,700,000 | $ 6,500,000 | $ 3,100,000 | |||
Accrued taxes | 2,112,000 | 26,340,000 | (8,405,000) | |||
Goodwill impairment charges | 0 | 0 | ||||
Reduction in depreciation expense due to extension of estimates useful lives | 10,000,000 | 4,000,000 | ||||
Non-service costs | 19,000,000 | 20,000,000 | ||||
Accounts Payable [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Capital expenditures incurred but not paid | 15,000,000 | |||||
Scenario, Forecast [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Corporate federal income tax rate | 21.00% | |||||
Centuri Construction Group Inc [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Intangible assets | 80,700,000 | 37,700,000 | ||||
Accounting Standards Update 2016-09 [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Accrued taxes | 27,400,000 | 23,200,000 | ||||
Accounting Standards Update 2016-09 [Member] | Scenario, Previously Reported [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Accrued taxes | 30,000,000 | 18,300,000 | ||||
Gas Plant [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Non-service costs capitalized | $ 3,000,000 | 3,000,000 | ||||
IntelliChoice Energy Llc [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Subsidiaries holding interest percentage | 65.00% | |||||
W.S. Nicholls Western Construction LTD [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Investment amount | $ 12,700,000 | 10,800,000 | ||||
Dividends | 0 | 500,000 | ||||
Exposure to loss as a result of its investment | 49,300,000 | |||||
Earnings from equity method investment | $ 1,100,000 | |||||
W.S. Nicholls Western Construction LTD [Member] | Centuri Construction Group Inc [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Subsidiaries holding interest percentage | 50.00% | |||||
Centuri Construction Group Inc [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Ownership percentage in subsidiary | 96.60% | 100.00% | ||||
Earnings from equity method investment | $ 1,052,000 | 69,000 | $ 310,000 | |||
Intangible assets | $ 80,702,000 | $ 37,669,000 | ||||
Previous Owners [Member] | Link-Line and WS Nicholls [Member] | Centuri Construction Group Inc [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Percentage of earnings attribution by Centuri to previous owners | 3.40% | |||||
Southwest Gas Corporation [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Number of operating segment | 1 | |||||
Corporate federal income tax rate | 35.00% | 35.00% | 35.00% | |||
Accrued taxes | $ 10,383,000 | $ 19,391,000 | $ (1,626,000) | |||
Southwest Gas Corporation [Member] | Scenario, Forecast [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Corporate federal income tax rate | 21.00% | |||||
Pooled Funds and Mutual Funds [Member] | Level 2 - Significant Other Observable Inputs [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Money market fund investments | 22,200,000 | 5,300,000 | ||||
Gas Pipe Materials and Supplies [Member] | Prepaids and Other Current Assets [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Gas pipe materials and operating supplies | 33,000,000 | $ 30,000,000 | ||||
Foreign Jurisdiction [Member] | ||||||
Significant Accounting Policies [Line Items] | ||||||
Cumulative earnings | $ 13,000,000 |
Summary of Significant Accoun45
Summary of Significant Accounting Policies - Schedule of Other Property and Investments (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Investment [Line Items] | ||
Other property | $ 13,242 | $ 11,034 |
Total | 428,180 | 342,343 |
Southwest Gas Corporation [Member] | ||
Investment [Line Items] | ||
Net cash surrender value of COLI policies | 117,341 | 106,744 |
Other property | 1,773 | 1,825 |
Total | 119,114 | 108,569 |
Centuri Construction Group Inc [Member] | ||
Investment [Line Items] | ||
Centuri property, equipment, and intangibles | 554,730 | 451,114 |
Centuri accumulated provision for depreciation and amortization | $ (258,906) | $ (228,374) |
Summary of Significant Accoun46
Summary of Significant Accounting Policies - Schedule of Goodwill (Detail) $ in Thousands | 12 Months Ended |
Dec. 31, 2017USD ($) | |
Goodwill [Line Items] | |
Goodwill, Beginning balance | $ 139,983 |
Foreign currency translation adjustment | 7,303 |
Goodwill, Ending balance | 179,314 |
New England Utility Constructors,Inc. [Member] | |
Goodwill [Line Items] | |
Additional goodwill from New England Utility Constructors, Inc. acquisition | 32,028 |
Southwest Gas [Member] | |
Goodwill [Line Items] | |
Goodwill, Beginning balance | 10,095 |
Goodwill, Ending balance | 10,095 |
Construction Services [Member] | |
Goodwill [Line Items] | |
Goodwill, Beginning balance | 129,888 |
Foreign currency translation adjustment | 7,303 |
Goodwill, Ending balance | 169,219 |
Construction Services [Member] | New England Utility Constructors,Inc. [Member] | |
Goodwill [Line Items] | |
Additional goodwill from New England Utility Constructors, Inc. acquisition | $ 32,028 |
Summary of Significant Accoun47
Summary of Significant Accounting Policies - Summary of Intangible Assets (Detail) - Centuri Construction Group Inc [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Finite-Lived Intangible Assets [Line Items] | ||
Gross Carrying Amount | $ 92,068 | $ 46,067 |
Accumulated Amortization | (11,366) | (8,398) |
Net Carrying Amount | 80,702 | 37,669 |
Customer Relationships [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross Carrying Amount | 76,254 | 34,033 |
Accumulated Amortization | (6,743) | (3,906) |
Net Carrying Amount | 69,511 | 30,127 |
Trade Names and Trademarks [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross Carrying Amount | 13,754 | 9,349 |
Accumulated Amortization | (4,080) | (2,565) |
Net Carrying Amount | 9,674 | 6,784 |
Customer Contracts Backlog [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross Carrying Amount | 1,656 | |
Accumulated Amortization | (1,656) | |
Noncompete Agreement [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross Carrying Amount | 2,060 | 1,029 |
Accumulated Amortization | (543) | (271) |
Net Carrying Amount | $ 1,517 | $ 758 |
Summary of Significant Accoun48
Summary of Significant Accounting Policies - Schedule of Estimated Future Amortization of Intangible Assets (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] | |
2,018 | $ 6,835 |
2,019 | 6,240 |
2,020 | 6,114 |
2,021 | 5,711 |
2,022 | $ 5,626 |
Summary of Significant Accoun49
Summary of Significant Accounting Policies - Schedule of Capitalized and Debt Portion of AFUDC (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Public Utilities, Allowance for Funds Used During Construction, Net Increase [Abstract] | |||
Debt portion | $ 1,666 | $ 1,175 | $ 1,666 |
Equity portion | 2,296 | 2,289 | 3,008 |
AFUDC capitalized as part of utility plant | $ 3,962 | $ 3,464 | $ 4,674 |
AFUDC rate | 5.95% | 7.35% | 7.32% |
Summary of Significant Accoun50
Summary of Significant Accounting Policies - Other Income (Deductions) (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Other income (deductions) | |||
Corporate and administrative | $ 13 | ||
Interest income | 2,787 | $ 1,849 | $ 2,173 |
Equity AFUDC | 2,296 | 2,289 | 3,008 |
Total other income (deductions) | 13,394 | 9,469 | 2,879 |
Southwest Gas Corporation [Member] | |||
Other income (deductions) | |||
Change in COLI policies | 10,300 | 7,400 | (500) |
Interest income | 2,784 | 1,848 | 1,754 |
Equity AFUDC | 2,296 | 2,289 | 3,008 |
Miscellaneous income and (expense) | (2,344) | (3,261) | (1,970) |
Total other income (deductions) | 13,036 | 8,276 | 2,292 |
Centuri Construction Group Inc [Member] | |||
Other income (deductions) | |||
Interest income | 3 | 1 | 419 |
Foreign transaction gain (loss) | (754) | (22) | (824) |
Equity in earnings of unconsolidated investment - Western | 1,052 | 69 | 310 |
Miscellaneous income and (expense) | 44 | 1,145 | 682 |
Total other income (deductions) | $ 345 | $ 1,193 | $ 587 |
Summary of Significant Accoun51
Summary of Significant Accounting Policies - Schedule of Earnings Per Share, Basic and Diluted (Detail) - shares shares in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Weighted Average Number of Shares Outstanding, Diluted [Abstract] | |||
Average basic shares | 47,965 | 47,469 | 46,992 |
Stock options | 1 | 8 | |
Management Incentive Plan shares | 8 | 124 | 171 |
Restricted stock units | 18 | 220 | 212 |
Average diluted shares | 47,991 | 47,814 | 47,383 |
Summary of Significant Accoun52
Summary of Significant Accounting Policies - Schedule of Earnings Per Share, Basic and Diluted (Parenthetical) (Detail) | 12 Months Ended |
Dec. 31, 2017shares | |
Weighted Average Number of Shares Outstanding, Diluted [Abstract] | |
Number of performance share units granted | 7,000 |
Utility Plant and Leases - Sche
Utility Plant and Leases - Schedule of Net Utility Plant (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | $ 6,629,644 | $ 6,193,760 |
Less: accumulated depreciation | (2,231,242) | (2,172,966) |
Construction work in progress | 125,248 | 111,177 |
Net utility plant | 4,523,650 | 4,131,971 |
Software and Software-related Intangibles [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | 230,030 | 224,260 |
Storage [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | 25,019 | 24,614 |
Transmission [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | 363,396 | 349,981 |
Distribution [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | 5,600,769 | 5,198,531 |
General [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | 396,252 | 382,084 |
Other [Member] | ||
Public Utility, Property, Plant and Equipment [Line Items] | ||
Gas plant | $ 14,178 | $ 14,290 |
Utility Plant and Leases - Addi
Utility Plant and Leases - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Public Utility, Property, Plant and Equipment [Line Items] | |||
Annual utility depreciation and amortization expense percentage | 2.90% | 3.60% | 3.60% |
Gas, Transmission and Distribution Plant [Member] | |||
Public Utility, Property, Plant and Equipment [Line Items] | |||
Annual utility depreciation and amortization expense percentage | 3.20% | 3.20% | 3.20% |
Gas plant [Member] | |||
Public Utility, Property, Plant and Equipment [Line Items] | |||
Amortization of intangibles | $ 14.3 | $ 14.8 | $ 12.7 |
Utility Plant and Leases - Sc55
Utility Plant and Leases - Schedule of Depreciation and Amortization Expense (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Public Utility, Property, Plant and Equipment [Line Items] | |||
Depreciation and amortization expense | $ 250,951 | $ 289,132 | $ 270,111 |
Gas plant [Member] | |||
Public Utility, Property, Plant and Equipment [Line Items] | |||
Depreciation and amortization expense | $ 187,075 | $ 214,037 | $ 201,233 |
Utility Plant and Leases - Sc56
Utility Plant and Leases - Schedule of Rental Payments for Operating Leases (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Rental Payments And Lease Payments Included In Operating Expenses [Line Items] | |||
Consolidated rental payments/lease expense | $ 67,236 | $ 58,313 | $ 50,035 |
Southwest Gas Corporation [Member] | |||
Rental Payments And Lease Payments Included In Operating Expenses [Line Items] | |||
Consolidated rental payments/lease expense | 4,926 | 4,357 | 4,186 |
Centuri Construction Group Inc [Member] | |||
Rental Payments And Lease Payments Included In Operating Expenses [Line Items] | |||
Consolidated rental payments/lease expense | $ 62,310 | $ 53,956 | $ 45,849 |
Utility Plant and Leases - Sc57
Utility Plant and Leases - Schedule of Future Minimum Lease Payments for Operating Leases (Detail) | Dec. 31, 2017USD ($) |
Operating Leased Assets [Line Items] | |
2,018 | $ 8,835 |
2,019 | 8,074 |
2,020 | 5,871 |
2,021 | 4,455 |
2,022 | 3,663 |
Thereafter | 9,646 |
Total minimum lease payments | 40,544 |
Southwest Gas [Member] | |
Operating Leased Assets [Line Items] | |
2,018 | 1,538 |
2,019 | 886 |
2,020 | 714 |
2,021 | 627 |
2,022 | 299 |
Thereafter | 116 |
Total minimum lease payments | 4,180 |
Centuri Construction Group Inc [Member] | |
Operating Leased Assets [Line Items] | |
2,018 | 7,297 |
2,019 | 7,188 |
2,020 | 5,157 |
2,021 | 3,828 |
2,022 | 3,364 |
Thereafter | 9,530 |
Total minimum lease payments | $ 36,364 |
Utility Plant and Leases - Sc58
Utility Plant and Leases - Schedule of Capital Leases of Equipment (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Leases [Abstract] | ||
Capital leased assets, gross | $ 2,159 | $ 3,189 |
Less: accumulated amortization | (1,000) | (1,172) |
Capital leased assets, net | $ 1,159 | $ 2,017 |
Utility Plant and Leases - Sc59
Utility Plant and Leases - Schedule of Future Minimum Lease Payments for Capital Leases (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Leases [Abstract] | |
2,018 | $ 709 |
2,019 | 233 |
2,020 | 191 |
2,021 | 0 |
2,022 | 0 |
Thereafter | 0 |
Future minimum lease payments due | 1,133 |
Less: amount representing interest | (84) |
Total minimum lease payments | $ 1,049 |
Revenue - Additional Informatio
Revenue - Additional Information (Detail) | 12 Months Ended |
Dec. 31, 2017Segment | |
Natural Gas Operations [Member] | |
Segment Reporting Information [Line Items] | |
Number of operating segment | 1 |
Receivables and Related Allow61
Receivables and Related Allowances - Schedule of Accounts Receivable (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Receivables [Abstract] | ||
Gas utility customer accounts receivable balance | $ 119,444 | $ 111,320 |
Receivables and Related Allow62
Receivables and Related Allowances - Schedule of Percent of Customers by State (Detail) | 12 Months Ended |
Dec. 31, 2017 | |
Arizona [Member] | |
Receivables And Related Allowances [Line Items] | |
Percent of customers by state | 53.00% |
Nevada [Member] | |
Receivables And Related Allowances [Line Items] | |
Percent of customers by state | 37.00% |
California [Member] | |
Receivables And Related Allowances [Line Items] | |
Percent of customers by state | 10.00% |
Receivables and Related Allow63
Receivables and Related Allowances - Schedule of Allowance for Uncollectibles (Detail) - Allowance for Uncollectibles [Member] - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Receivables And Related Allowances [Line Items] | |||
Beginning Balance | $ 2,524 | $ 2,270 | $ 2,255 |
Additions charged to expense | 2,310 | 3,264 | 4,113 |
Accounts written off, less recoveries | (2,723) | (3,010) | (4,098) |
Ending Balance | $ 2,111 | $ 2,524 | $ 2,270 |
Receivables and Related Allow64
Receivables and Related Allowances - Additional Information (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Receivables And Related Allowances [Line Items] | ||
Customer accounts receivable | $ 347,375 | $ 285,145 |
Centuri Construction Group Inc [Member] | ||
Receivables And Related Allowances [Line Items] | ||
Customer accounts receivable | $ 227,600 |
Regulatory Assets and Liabili65
Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | $ 531,898 | $ 477,743 |
Net regulatory assets (liabilities) | (266,288) | 40,442 |
Regulatory liabilities, total | (33,184) | (18,066) |
Accrued Pension and Other Postretirement Benefit Costs [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 391,403 | 379,063 |
Unrealized Net Loss on Non-trading Derivatives (Swaps) [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 5,780 | |
Regulatory liabilities, total | (4,377) | |
Deferred Purchased Gas Costs [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 14,581 | 2,608 |
Regulatory liabilities, total | (6,841) | (90,476) |
Accrued Purchased Gas Costs [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 17,000 | 37,100 |
Unamortized Premium on Reacquired Debt [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 20,913 | 21,975 |
Accrued Absence Time [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 13,870 | 13,440 |
Other [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets, total | 68,351 | 23,557 |
Accumulated Removal Costs [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory liabilities, total | (315,000) | (308,000) |
Unamortized Gain on Reacquired Debt [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory liabilities, total | (9,253) | (9,789) |
Regulatory Excess Deferred Taxes and Gross-up [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory liabilities, total | (433,908) | (6,593) |
Other [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory liabilities, total | $ (33,184) | $ (18,066) |
Regulatory Assets and Liabili66
Regulatory Assets and Liabilities - Schedule of Regulatory Assets and Liabilities (Parenthetical) (Detail) - Swaps [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Deferred Charges and Other Assets [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets and liabilities offsetting derivatives at fair value | $ 1,323 | |
Prepaids and Other Current Assets [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets and liabilities offsetting derivatives at fair value | $ 4,457 | |
Other Current Liabilities [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets and liabilities offsetting derivatives at fair value | $ (3,532) | |
Other Deferred Credits [Member] | ||
Regulatory Assets And Liabilities [Line Items] | ||
Regulatory assets and liabilities offsetting derivatives at fair value | $ (845) |
Regulatory Assets and Liabili67
Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Assets are Included in either Prepaids and Other Current Assets or Deferred Credits and Other Assets on the Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 531,898 | $ 477,743 |
State Mandate Public Purpose Programs (Including Low Income and Conservation Programs) [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 4,832 | 7,096 |
Margin, Interest- and Property Tax-Tracking Accounts [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 42,354 | 3,517 |
Environmental Compliance Programs [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 9,702 | 4,329 |
Infrastructure Replacement Programs and Similar [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 9,627 | 6,976 |
Other [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | 1,836 | 1,639 |
Other Regulatory Assets [Member] | ||
Regulatory Assets [Line Items] | ||
Regulatory assets | $ 68,351 | $ 23,557 |
Regulatory Assets and Liabili68
Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Assets are Included in Deferred Credits and Other Assets on the Consolidated Balance Sheets (Parenthetical) (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Assets [Line Items] | ||
Prepaid and other current assets | $ 165,294 | $ 136,833 |
Deferred charges and other assets | 447,410 | 432,234 |
Environmental Compliance Programs [Member] | ||
Regulatory Assets [Line Items] | ||
Prepaid and other current assets | 9,200 | 3,800 |
Deferred charges and other assets | 527,000 | 500,000 |
Other Regulatory Assets [Member] | ||
Regulatory Assets [Line Items] | ||
Prepaid and other current assets | 531,000 | 622,000 |
Deferred charges and other assets | $ 1,300 | $ 1,000 |
Regulatory Assets and Liabili69
Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Liabilities are Included in either Other Current Liabilities or Deferred Credits and Other Liabilities on Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | $ (33,184) | $ (18,066) |
Other Regulatory Liabilities [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | (1,714) | (544) |
Margin, Interest- and Property Tax-Tracking Accounts [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | (9,505) | (3,668) |
State Mandate Public Purpose Programs (Including Low Income and Conservation Programs) [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | (10,213) | (7,101) |
Environmental Compliance Programs [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | (8,574) | (4,469) |
Regulatory Accounts for Differences Related to Pension Funding [Member] | ||
Regulatory Liabilities [Line Items] | ||
Regulatory liabilities | $ (3,178) | $ (2,284) |
Regulatory Assets and Liabili70
Regulatory Assets and Liabilities - Schedule of Components of Other Regulatory Liabilities are Included in either Other Current Liabilities or Deferred Credits and Other Liabilities on Consolidated Balance Sheets (Parenthetical) (Detail) - USD ($) | Dec. 31, 2017 | Dec. 31, 2016 |
Regulatory Liabilities [Line Items] | ||
Other current liabilities | $ 203,403,000 | $ 168,064,000 |
Other deferred credits and other long-term liabilities | 1,018,246,000 | 570,252,000 |
Other Regulatory Liabilities [Member] | ||
Regulatory Liabilities [Line Items] | ||
Other current liabilities | 1,700,000 | 536,000 |
Other deferred credits and other long-term liabilities | 9,000 | $ 8,000 |
Margin, Interest- and Property Tax-Tracking Accounts [Member] | ||
Regulatory Liabilities [Line Items] | ||
Other current liabilities | 6,600,000 | |
Other deferred credits and other long-term liabilities | $ 2,900,000 |
Other Comprehensive Income an71
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
Net actuarial gain/(loss), Before-Tax Amount | $ (43,027) | $ (22,770) | $ (30,519) |
Amortization of prior service cost, Before-Tax Amount | 1,335 | 1,335 | 1,335 |
Amortization of net actuarial (gain)/loss, Before-Tax Amount | 25,445 | 27,066 | 34,381 |
Regulatory adjustment, Before-Tax Amount | 12,340 | (5,584) | (5,646) |
Net current period other comprehensive income (loss), Defined Benefit Plans Before-Tax | (3,907) | 47 | (449) |
Amounts reclassified into net income, Before-Tax Amount | 3,344 | 3,345 | 3,344 |
FSIRS other comprehensive income (loss), Before-Tax Amount | 3,344 | 3,345 | 3,344 |
Total other comprehensive income (loss), Before-Tax Amount | 1,208 | 3,553 | 941 |
Translation adjustments, Before-Tax Amount | 1,771 | 161 | (1,954) |
Foreign currency other comprehensive income (loss), Before-Tax Amount | 1,771 | 161 | (1,954) |
Net actuarial gain/(loss), Tax (Expense) or Benefit | 10,326 | 8,652 | 11,597 |
Amortization of prior service cost, Tax (Expense) or Benefit | (507) | (507) | (507) |
Amortization of net actuarial (gain)/loss, Tax (Expense) or Benefit | (9,669) | (10,285) | (13,065) |
Regulatory adjustment, Tax (Expense) or Benefit | 250 | 2,122 | 2,146 |
Pension plans other comprehensive income (loss), Tax (Expense) or Benefit | 400 | (18) | 171 |
Amounts reclassified into net income, Tax (Expense) or Benefit | (1,271) | (1,270) | (1,271) |
FSIRS other comprehensive income (loss), Tax (Expense) or Benefit | (1,271) | (1,270) | (1,271) |
Total other comprehensive income (loss), Tax (Expense) or Benefit | 871 | 1,288 | 1,100 |
Translation adjustments, Tax (Expense) or Benefit | 0 | 0 | 0 |
Foreign currency other comprehensive income (loss), Tax (Expense) or Benefit | 0 | 0 | 0 |
Net actuarial gain/(loss), Before-Tax Amount | (32,701) | (14,118) | (18,922) |
Amortization of prior service cost, Net-of-Tax Amount | 828 | 828 | 828 |
Amortization of net actuarial (gain)/loss, Defined Benefit Plans After-Tax | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, Net-of-Tax Amount | 12,590 | (3,462) | (3,500) |
Net defined benefit pension plans | (3,507) | 29 | (278) |
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
FSIRS other comprehensive income (loss), Net-of-Tax Amount | 2,073 | 2,075 | 2,073 |
Total other comprehensive income (loss), net of tax | 337 | 2,265 | (159) |
Southwest Gas Corporation [Member] | |||
Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
Net actuarial gain/(loss), Before-Tax Amount | (43,027) | ||
Amortization of prior service cost, Before-Tax Amount | 1,335 | ||
Amortization of net actuarial (gain)/loss, Before-Tax Amount | 25,445 | ||
Regulatory adjustment, Before-Tax Amount | 12,340 | ||
Amounts reclassified into net income, Before-Tax Amount | 3,344 | ||
Total other comprehensive income (loss), Before-Tax Amount | (563) | 3,392 | 2,895 |
Net actuarial gain/(loss), Tax (Expense) or Benefit | 10,326 | ||
Amortization of prior service cost, Tax (Expense) or Benefit | (507) | ||
Amortization of net actuarial (gain)/loss, Tax (Expense) or Benefit | (9,669) | ||
Regulatory adjustment, Tax (Expense) or Benefit | 250 | ||
Amounts reclassified into net income, Tax (Expense) or Benefit | (1,271) | ||
Total other comprehensive income (loss), Tax (Expense) or Benefit | (871) | (1,288) | (1,100) |
Net actuarial gain/(loss), Before-Tax Amount | (32,701) | (14,118) | (18,922) |
Amortization of prior service cost, Net-of-Tax Amount | 828 | 828 | 828 |
Amortization of net actuarial (gain)/loss, Defined Benefit Plans After-Tax | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, Net-of-Tax Amount | 12,590 | (3,462) | (3,500) |
Net defined benefit pension plans | (3,507) | 29 | (278) |
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
FSIRS other comprehensive income (loss), Net-of-Tax Amount | 2,073 | 2,075 | 2,073 |
Total other comprehensive income (loss), net of tax | $ (1,434) | $ 2,104 | $ 1,795 |
Other Comprehensive Income an72
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Parenthetical) (Detail) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 25.10% | 33.90% | 36.40% | |
Tax Cuts and Jobs Act [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 38.00% | |||
Tax Cuts and Jobs Act [Member] | Scenario, Forecast [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 24.00% |
Other Comprehensive Income an73
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Schedule of Estimated Amounts Amortized from Accumulated Other Comprehensive Income or Regulatory Assets into Net Periodic Benefit Cost (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Qualified Retirement Plan [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Retirement plan net actuarial loss | $ 32,000 |
SERP [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
Retirement plan net actuarial loss | 1,500 |
PBOP [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
PBOP prior service cost | $ 1,300 |
Other Comprehensive Income an74
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Rollforward of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans Before-Tax | $ (57,613) | ||
Net actuarial gain/(loss), Defined Benefit Plans Before-Tax | (43,027) | $ (22,770) | $ (30,519) |
Translation adjustments, Defined Benefit Plans Before-Tax | 0 | ||
Other comprehensive income before reclassifications, Defined Benefit Plans Before-Tax | (43,027) | ||
Amortization of prior service cost, Defined Benefit Plans Before-Tax | 1,335 | 1,335 | 1,335 |
Amortization of net actuarial loss, Defined Benefit Plans Before-Tax | 25,445 | 27,066 | 34,381 |
Regulatory adjustment, Defined Benefit Plans Before-Tax | 12,340 | (5,584) | (5,646) |
Net current period other comprehensive income (loss), Defined Benefit Plans Before-Tax | (3,907) | 47 | (449) |
Less: Translation adjustment attributable to redeemable noncontrolling interest, Defined Benefit Plans Before-Tax | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans Before-Tax | (3,907) | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans Before-Tax | (61,520) | (57,613) | |
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans Tax (Expense) Benefit | 21,893 | ||
Net actuarial gain/(loss), Defined Benefit Plans Tax (Expense) Benefit | 10,326 | 8,652 | 11,597 |
Translation adjustments, Defined Benefit Plans Tax (Expense) Benefit | 0 | ||
Other comprehensive income before reclassifications, Defined Benefit Plans Tax (Expense) Benefit | 10,326 | ||
Amortization of prior service cost, Defined Benefit Plans Tax (Expense) Benefit | (507) | (507) | (507) |
Amortization of net actuarial loss, Defined Benefit Plans Tax (Expense) Benefit | (9,669) | (10,285) | (13,065) |
Regulatory adjustment, Defined Benefit Plans Tax (Expense) Benefit | 250 | 2,122 | 2,146 |
Pension plans other comprehensive income (loss), Tax (Expense) or Benefit | 400 | (18) | 171 |
Less: Translation adjustment attributable to redeemable noncontrolling interest, Defined Benefit Plans Tax (Expense) Benefit | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans Tax (Expense) Benefit | 400 | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans Tax (Expense) Benefit | 22,293 | 21,893 | |
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans After-Tax | (35,720) | ||
Net actuarial gain/(loss), Defined Benefit Plans After-Tax | (32,701) | (14,118) | (18,922) |
Translation adjustments, Defined Benefit Plans After-Tax | 0 | ||
Other comprehensive income before reclassifications, Defined Benefit Plans After-Tax | (32,701) | ||
Amortization of prior service cost, Defined Benefit Plans After-Tax | 828 | 828 | 828 |
Amortization of net actuarial (gain)/loss, Defined Benefit Plans After-Tax | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, Defined Benefit Plans After-Tax | 12,590 | ||
Net defined benefit pension plans | (3,507) | 29 | (278) |
Less: Translation adjustment attributable to redeemable noncontrolling interest, Defined Benefit Plans After-Tax | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans After-Tax | (3,507) | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans After-Tax | (39,227) | (35,720) | |
Beginning Balance AOCI December 31, 2016, FSIRS - Before-Tax | (15,999) | ||
Net actuarial gain/(loss), FSIRS - Before-Tax | 0 | ||
Translation adjustments, FSIRS - Before-Tax | 0 | ||
Other comprehensive income before reclassifications, FSIRS - Before-Tax | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - Before-Tax | 3,344 | 3,345 | 3,344 |
Net current period other comprehensive income (loss), FSIRS - Before-Tax | 3,344 | 3,345 | 3,344 |
Less: Translation adjustment attributable to redeemable noncontrolling interest, FSIRS - Before-Tax | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - Before-Tax | 3,344 | ||
Ending Balance AOCI December 31, 2017, FSIRS - Before-Tax | (12,655) | (15,999) | |
Beginning Balance AOCI December 31, 2016, FSIRS - Tax (Expense) Benefit | 6,080 | ||
Net actuarial gain/(loss), FSIRS - Tax (Expense) Benefit | 0 | ||
Translation adjustments, FSIRS - Tax (Expense) Benefit | 0 | ||
Other comprehensive income before reclassifications, FSIRS - Tax (Expense) Benefit | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - Tax (Expense) Benefit | (1,271) | (1,270) | (1,271) |
Net current period other comprehensive income (loss), FSIRS - Tax (Expense) Benefit | (1,271) | (1,270) | (1,271) |
Less: Translation adjustment attributable to redeemable noncontrolling interest, FSIRS - Tax (Expense) Benefit | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - Tax (Expense) Benefit | (1,271) | ||
Ending Balance AOCI December 31, 2017, FSIRS - Tax (Expense) Benefit | 4,809 | 6,080 | |
Beginning Balance AOCI December 31, 2016, FSIRS - After-Tax | (9,919) | ||
Net actuarial gain/(loss), FSIRS - After-Tax | 0 | ||
Translation adjustments, FSIRS - After-Tax | 0 | ||
Other comprehensive income before reclassifications | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - After-Tax | 2,073 | 2,075 | 2,073 |
Net current period other comprehensive income (loss) | 2,073 | 2,075 | 2,073 |
Less: Translation adjustment attributable to redeemable noncontrolling interest | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - After-Tax | 2,073 | ||
Ending Balance AOCI December 31, 2017, FSIRS - After-Tax | (7,846) | (9,919) | |
Beginning Balance AOCI December 31, 2016, Foreign Currency Items Before-Tax | (2,369) | ||
Net actuarial gain/(loss), Foreign Currency Items Before-Tax | 0 | ||
Translation adjustments, Foreign Currency Items Before-Tax | 1,771 | 161 | (1,954) |
Other comprehensive income before reclassifications | 1,771 | 161 | (1,954) |
FSIRS amounts reclassified from AOCI, Foreign Currency Items Before-Tax | 0 | ||
Amortization of prior service cost, Foreign Currency Items Before-Tax | 0 | ||
Amortization of net actuarial loss, Foreign Currency Items Before-Tax | 0 | ||
Regulatory adjustment, Foreign Currency Items Before-Tax | 0 | ||
Net current period other comprehensive income (loss) | 1,771 | ||
Less: Translation adjustment attributable to redeemable noncontrolling interest, Foreign Currency Items Before-Tax | 11 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Holdings, Inc., Foreign Currency Items Before-Tax | 1,760 | 156 | (1,888) |
Ending Balance AOCI December 31, 2017 | (609) | (2,369) | |
Beginning Balance AOCI December 31, 2016, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Net actuarial gain/(loss), Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Translation adjustments, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Other comprehensive income before reclassifications, Foreign Currency items - Tax (Expense) Benefit | 0 | 0 | 0 |
FSIRS amounts reclassified from AOCI, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Amortization of prior service cost ,Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Amortization of net actuarial loss, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Regulatory adjustment, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Net current period other comprehensive income (loss), Foreign Currency items - Tax (Expense) Benefit | 0 | 0 | 0 |
Less: Translation adjustment attributable to redeemable noncontrolling interest, Foreign Currency items - Tax (Expense) Benefit | 0 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Holdings, Inc., Foreign Currency items - Tax (Expense) Benefit | 0 | 0 | 0 |
Ending Balance AOCI December 31, 2017, Foreign Currency items - Tax (Expense) Benefit | 0 | 0 | |
Beginning Balance AOCI December 31, 2016, Foreign Currency items - After-Tax | (2,369) | ||
Net actuarial gain (loss), Foreign Currency items - After-Tax | 0 | ||
Translation adjustments, Foreign Currency items - After-Tax | 1,771 | ||
Other comprehensive income before reclassifications, Foreign Currency items - After-Tax | 1,771 | 161 | (1,954) |
FSIRS amounts reclassified from AOCI, Foreign Currency items - After-Tax | 0 | ||
Amortization of prior service cost, Foreign Currency items - After-Tax | 0 | ||
Amortization of net actuarial loss, Foreign Currency items - After-Tax | 0 | ||
Regulatory adjustment, Foreign Currency items - After-Tax | 0 | ||
Net current period other comprehensive income (loss), Foreign Currency items - After-Tax | 1,771 | ||
Less: Translation adjustment attributable to redeemable noncontrolling interest, Foreign Currency items - After-Tax | 11 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Holdings, Inc., Foreign Currency Items - After-Tax | 1,760 | ||
Ending Balance AOCI December 31, 2017, Foreign Currency items - After-Tax | (609) | (2,369) | |
Beginning Balance AOCI December 31, 2016, AOCI | (48,008) | ||
Net actuarial gain (loss), AOCI | (32,701) | (14,118) | (18,922) |
Translation adjustments, AOCI | 1,771 | ||
Other comprehensive income before reclassifications, AOCI | (30,930) | ||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
Amortization of prior service cost, AOCI | 828 | 828 | 828 |
Amortization of net actuarial loss | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, AOCI | 12,590 | ||
Total other comprehensive income (loss), net of tax | 337 | 2,265 | (159) |
Less: Translation adjustment attributable to redeemable noncontrolling interest, AOCI | 11 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, AOCI | 326 | ||
Ending Balance AOCI December 31, 2017, AOCI | (47,682) | (48,008) | |
Southwest Gas Corporation [Member] | |||
Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans Before-Tax | (57,613) | ||
Net actuarial gain/(loss), Defined Benefit Plans Before-Tax | (43,027) | ||
Other comprehensive income before reclassifications, Defined Benefit Plans Before-Tax | (43,027) | ||
Amortization of prior service cost, Defined Benefit Plans Before-Tax | 1,335 | ||
Amortization of net actuarial loss, Defined Benefit Plans Before-Tax | 25,445 | ||
Regulatory adjustment, Defined Benefit Plans Before-Tax | 12,340 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans Before-Tax | (3,907) | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans Before-Tax | (61,520) | (57,613) | |
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans Tax (Expense) Benefit | 21,893 | ||
Net actuarial gain/(loss), Defined Benefit Plans Tax (Expense) Benefit | 10,326 | ||
Other comprehensive income before reclassifications, Defined Benefit Plans Tax (Expense) Benefit | 10,326 | ||
Amortization of prior service cost, Defined Benefit Plans Tax (Expense) Benefit | (507) | ||
Amortization of net actuarial loss, Defined Benefit Plans Tax (Expense) Benefit | (9,669) | ||
Regulatory adjustment, Defined Benefit Plans Tax (Expense) Benefit | 250 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans Tax (Expense) Benefit | 400 | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans Tax (Expense) Benefit | 22,293 | 21,893 | |
Beginning Balance AOCI December 31, 2016, Defined Benefit Plans After-Tax | (35,720) | ||
Net actuarial gain/(loss), Defined Benefit Plans After-Tax | (32,701) | (14,118) | (18,922) |
Other comprehensive income before reclassifications, Defined Benefit Plans After-Tax | (32,701) | ||
Amortization of prior service cost, Defined Benefit Plans After-Tax | 828 | 828 | 828 |
Amortization of net actuarial (gain)/loss, Defined Benefit Plans After-Tax | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, Defined Benefit Plans After-Tax | 12,590 | ||
Net defined benefit pension plans | (3,507) | 29 | (278) |
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, Defined Benefit Plans After-Tax | (3,507) | ||
Ending Balance AOCI December 31, 2017, Defined Benefit Plans After-Tax | (39,227) | (35,720) | |
Beginning Balance AOCI December 31, 2016, FSIRS - Before-Tax | (15,999) | ||
Net actuarial gain/(loss), FSIRS - Before-Tax | 0 | ||
Other comprehensive income before reclassifications, FSIRS - Before-Tax | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - Before-Tax | 3,344 | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - Before-Tax | 3,344 | ||
Ending Balance AOCI December 31, 2017, FSIRS - Before-Tax | (12,655) | (15,999) | |
Beginning Balance AOCI December 31, 2016, FSIRS - Tax (Expense) Benefit | 6,080 | ||
Net actuarial gain/(loss), FSIRS - Tax (Expense) Benefit | 0 | ||
Other comprehensive income before reclassifications, FSIRS - Tax (Expense) Benefit | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - Tax (Expense) Benefit | (1,271) | ||
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - Tax (Expense) Benefit | (1,271) | ||
Ending Balance AOCI December 31, 2017, FSIRS - Tax (Expense) Benefit | 4,809 | 6,080 | |
Beginning Balance AOCI December 31, 2016, FSIRS - After-Tax | (9,919) | ||
Other comprehensive income before reclassifications | 0 | ||
FSIRS amounts reclassified from AOCI, FSIRS - After-Tax | 2,073 | 2,075 | 2,073 |
Net current period other comprehensive income (loss) | 2,073 | 2,075 | 2,073 |
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, FSIRS - After-Tax | 2,073 | ||
Ending Balance AOCI December 31, 2017, FSIRS - After-Tax | (7,846) | (9,919) | |
Beginning Balance AOCI December 31, 2016, AOCI | (45,639) | ||
Net actuarial gain (loss), AOCI | (32,701) | (14,118) | (18,922) |
Other comprehensive income before reclassifications, AOCI | (32,701) | ||
Amounts reclassified into net income (Notes 6 and 14) | 2,073 | 2,075 | 2,073 |
Amortization of prior service cost, AOCI | 828 | 828 | 828 |
Amortization of net actuarial loss | 15,776 | 16,781 | 21,316 |
Regulatory adjustment, AOCI | 12,590 | ||
Total other comprehensive income (loss), net of tax | (1,434) | 2,104 | $ 1,795 |
Net current period other comprehensive income (loss) attributable to Southwest Gas Corporation, AOCI | (1,434) | ||
Ending Balance AOCI December 31, 2017, AOCI | $ (47,073) | $ (45,639) |
Other Comprehensive Income an75
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Rollforward of Accumulated Other Comprehensive Income (Parenthetical) (Detail) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 25.10% | 33.90% | 36.40% | |
Effective income tax rate | 25.10% | 33.90% | 36.40% | |
Southwest Gas Corporation [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 28.70% | 32.90% | 35.50% | |
Effective income tax rate | 28.70% | 32.90% | 35.50% | |
Tax Cuts and Jobs Act [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 38.00% | |||
Effective income tax rate | 38.00% | |||
Tax Cuts and Jobs Act [Member] | Scenario, Forecast [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 24.00% | |||
Effective income tax rate | 24.00% | |||
Tax Cuts and Jobs Act [Member] | Southwest Gas Corporation [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 38.00% | |||
Effective income tax rate | 38.00% | |||
Tax Cuts and Jobs Act [Member] | Southwest Gas Corporation [Member] | Scenario, Forecast [Member] | ||||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||||
Effective income tax rate | 24.00% | |||
Effective income tax rate | 24.00% |
Other Comprehensive Income an76
Other Comprehensive Income and Accumulated Other Comprehensive Income ("AOCI") - Amount Recognized Before Income Tax Associated with Defined Benefit Plans in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||
Less: amount recognized in regulatory assets | $ 531,898 | $ 477,743 |
Recognized in AOCI | (61,520) | (57,613) |
Defined Benefit Plans [Member] | ||
Accumulated Other Comprehensive Income (Loss) [Line Items] | ||
Net actuarial (loss) gain | (448,555) | (430,973) |
Prior service cost | (4,368) | (5,703) |
Less: amount recognized in regulatory assets | 391,403 | 379,063 |
Recognized in AOCI | $ (61,520) | $ (57,613) |
Common Stock - Additional Infor
Common Stock - Additional Information (Detail) | Mar. 29, 2017USD ($) | Jan. 31, 2017 | Dec. 31, 2017USD ($)$ / sharesshares | Dec. 31, 2017USD ($)$ / sharesshares | Dec. 31, 2016USD ($) | Dec. 31, 2015USD ($) |
Conversion of stock conversion ratio | 1 | |||||
Value of common stock | $ 150,000,000 | |||||
Net proceeds to company | $ 41,155,000 | $ 472,000 | $ 35,396,000 | |||
Common stock issued through Restricted Stock/Unit Plan, and Management Incentive Plan | shares | 103,000 | |||||
BNY Mellon Capital Markets, LLC [Member] | ||||||
Common stock sold through agent | shares | 358,630 | 505,707 | ||||
Open market weighted average price per share | $ / shares | $ 83.65 | $ 82.61 | ||||
Net proceeds to company | $ 29,699,923 | $ 41,359,027 | ||||
Agent commissions | 299,999 | 417,768 | ||||
Common stock available for sale under the program | $ 108,223,205 | $ 108,223,205 |
Long-Term Debt - Schedule of Ca
Long-Term Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Debt Instrument [Line Items] | ||
Less: current maturities | $ (25,346) | $ (50,101) |
Long-term debt, less current maturities | 1,798,576 | 1,549,983 |
Long-term Debt, Current and Noncurrent Abstract | ||
Less: current maturities | (25,346) | (50,101) |
Long-term debt, less current maturities | 1,798,576 | 1,549,983 |
Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Less: current maturities | (25,000) | |
Long-term debt, less current maturities | 1,521,031 | 1,375,080 |
Long-term Debt, Current and Noncurrent Abstract | ||
Less: current maturities | (25,000) | |
Long-term debt, less current maturities | 1,521,031 | 1,375,080 |
IDRBs [Member] | 2009 Series A, due 2039 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt, fair value | 50,000 | 50,000 |
Carrying Amount [Member] | ||
Debt Instrument [Line Items] | ||
Less: current maturities | (25,346) | (50,101) |
Long-term debt, less current maturities | 1,798,576 | 1,549,983 |
Long-term Debt, Current and Noncurrent Abstract | ||
Less: current maturities | (25,346) | (50,101) |
Long-term debt, less current maturities | 1,798,576 | 1,549,983 |
Carrying Amount [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Less: current maturities | (25,000) | |
Long-term debt, less current maturities | 1,521,031 | 1,375,080 |
Long-term Debt, Current and Noncurrent Abstract | ||
Long-term debt | 1,521,031 | 1,400,080 |
Less: current maturities | (25,000) | |
Long-term debt, less current maturities | 1,521,031 | 1,375,080 |
Carrying Amount [Member] | Centuri Construction Group Inc [Member] | ||
Debt Instrument [Line Items] | ||
Less: current maturities | (25,346) | (25,101) |
Long-term debt, less current maturities | 277,545 | 174,903 |
Unamortized debt issuance costs | (1,111) | (516) |
Long-term Debt, Current and Noncurrent Abstract | ||
Long-term debt | 302,891 | 200,004 |
Less: current maturities | (25,346) | (25,101) |
Long-term debt, less current maturities | 277,545 | 174,903 |
Centuri term loan/secured revolving credit facility | 198,467 | 106,184 |
Carrying Amount [Member] | Centuri Secured Revolving Credit Facility [Member] | Centuri Construction Group Inc [Member] | ||
Long-term Debt, Current and Noncurrent Abstract | ||
Centuri term loan/secured revolving credit facility | 56,472 | 41,185 |
Carrying Amount [Member] | Centuri Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | ||
Long-term Debt, Current and Noncurrent Abstract | ||
Centuri term loan/secured revolving credit facility | 199,578 | 106,700 |
Carrying Amount [Member] | Centuri Other Debt Obligations [Member] | Centuri Construction Group Inc [Member] | ||
Long-term Debt, Current and Noncurrent Abstract | ||
Centuri other debt obligations | 47,952 | 52,635 |
Carrying Amount [Member] | Debentures [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unamortized discount and debt issuance costs | (9,350) | (9,931) |
Notes payable | 1,173,150 | 1,197,569 |
Carrying Amount [Member] | Debentures [Member] | Notes, 4.45%, due 2020 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 125,000 | 125,000 |
Carrying Amount [Member] | Debentures [Member] | Notes, 6.1%, due 2041 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 125,000 | 125,000 |
Carrying Amount [Member] | Debentures [Member] | Notes, 3.875%, due 2022 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 250,000 | 250,000 |
Carrying Amount [Member] | Debentures [Member] | Notes, 4.875%, due 2043 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 250,000 | 250,000 |
Carrying Amount [Member] | Debentures [Member] | Notes, 3.8%, due 2046 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 300,000 | 300,000 |
Carrying Amount [Member] | Debentures [Member] | 8% Series, due 2026 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 75,000 | 75,000 |
Carrying Amount [Member] | Debentures [Member] | Medium-term notes, 7.59% series, due 2017 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 25,000 | |
Carrying Amount [Member] | Debentures [Member] | Medium-term notes, 7.78% series, due 2022 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 25,000 | 25,000 |
Carrying Amount [Member] | Debentures [Member] | Medium-term notes, 7.92% series, due 2027 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 25,000 | 25,000 |
Carrying Amount [Member] | Debentures [Member] | Medium-term notes, 6.76% series, due 2027 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable | 7,500 | 7,500 |
Carrying Amount [Member] | Debentures [Member] | Revolving Credit Facility and Commercial Paper [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Line of credit facility | 150,000 | 5,000 |
Carrying Amount [Member] | IDRBs [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unamortized discount and debt issuance costs | (2,119) | (2,489) |
Unsecured debt | 197,881 | 197,511 |
Carrying Amount [Member] | IDRBs [Member] | Tax-exempt Series A, due 2028 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt | 50,000 | 50,000 |
Carrying Amount [Member] | IDRBs [Member] | 2003 Series A, due 2038 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt | 50,000 | 50,000 |
Carrying Amount [Member] | IDRBs [Member] | 2008 Series A, due 2038 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt | 50,000 | 50,000 |
Carrying Amount [Member] | IDRBs [Member] | 2009 Series A, due 2039 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt | 50,000 | 50,000 |
Market Value [Member] | Centuri Construction Group Inc [Member] | ||
Long-term Debt, Current and Noncurrent Abstract | ||
Centuri term loan/secured revolving credit facility | 207,588 | 106,819 |
Centuri other debt obligations | 48,183 | 52,840 |
Market Value [Member] | Centuri Secured Revolving Credit Facility [Member] | Centuri Construction Group Inc [Member] | ||
Long-term Debt, Current and Noncurrent Abstract | ||
Centuri term loan/secured revolving credit facility | 56,525 | 41,292 |
Market Value [Member] | Debentures [Member] | Notes, 4.45%, due 2020 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 129,273 | 129,703 |
Market Value [Member] | Debentures [Member] | Notes, 6.1%, due 2041 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 158,304 | 149,734 |
Market Value [Member] | Debentures [Member] | Notes, 3.875%, due 2022 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 256,163 | 254,900 |
Market Value [Member] | Debentures [Member] | Notes, 4.875%, due 2043 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 283,243 | 266,793 |
Market Value [Member] | Debentures [Member] | Notes, 3.8%, due 2046 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 302,970 | 283,029 |
Market Value [Member] | Debentures [Member] | 8% Series, due 2026 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 96,063 | 94,691 |
Market Value [Member] | Debentures [Member] | Medium-term notes, 7.59% series, due 2017 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 25,040 | |
Market Value [Member] | Debentures [Member] | Medium-term notes, 7.78% series, due 2022 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 28,714 | 29,290 |
Market Value [Member] | Debentures [Member] | Medium-term notes, 7.92% series, due 2027 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 31,542 | 31,905 |
Market Value [Member] | Debentures [Member] | Medium-term notes, 6.76% series, due 2027 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Notes payable, fair value disclosure | 8,882 | 8,769 |
Market Value [Member] | Debentures [Member] | Revolving Credit Facility and Commercial Paper [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Line of credit facility, fair value | 150,000 | 5,000 |
Market Value [Member] | IDRBs [Member] | Tax-exempt Series A, due 2028 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt, fair value | 50,000 | 50,000 |
Market Value [Member] | IDRBs [Member] | 2003 Series A, due 2038 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt, fair value | 50,000 | 50,000 |
Market Value [Member] | IDRBs [Member] | 2008 Series A, due 2038 [Member] | Southwest Gas Corporation [Member] | ||
Debt Instrument [Line Items] | ||
Unsecured debt, fair value | $ 50,000 | $ 50,000 |
Long-Term Debt - Schedule of 79
Long-Term Debt - Schedule of Carrying Amounts and Estimated Fair Values of Long-Term Debt (Parenthetical) (Detail) - Southwest Gas Corporation [Member] | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Debentures [Member] | Medium-term notes, 7.59% series, due 2017 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 7.59% | 7.59% |
Debt instrument due date | Jan. 17, 2017 | Jan. 17, 2017 |
Debentures [Member] | Notes, 4.45%, due 2020 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 4.45% | 4.45% |
Debt instrument due date | Dec. 1, 2020 | Dec. 1, 2020 |
Debentures [Member] | Notes, 6.1%, due 2041 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 6.10% | 6.10% |
Debt instrument due date | Feb. 15, 2041 | Feb. 15, 2041 |
Debentures [Member] | Notes, 3.875%, due 2022 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 3.875% | 3.875% |
Debt instrument due date | Apr. 1, 2022 | Apr. 1, 2022 |
Debentures [Member] | Notes, 4.875%, due 2043 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 4.875% | 4.875% |
Debt instrument due date | Oct. 1, 2043 | Oct. 1, 2043 |
Debentures [Member] | Notes, 3.8%, due 2046 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 3.80% | 3.80% |
Debt instrument due date | Sep. 30, 2046 | Sep. 30, 2046 |
Debentures [Member] | 8% Series, due 2026 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 8.00% | 8.00% |
Debt instrument due date | Aug. 1, 2026 | Aug. 1, 2026 |
Debentures [Member] | Medium-term notes, 7.78% series, due 2022 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 7.78% | 7.78% |
Debt instrument due date | Feb. 3, 2022 | Feb. 3, 2022 |
Debentures [Member] | Medium-term notes, 7.92% series, due 2027 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 7.92% | 7.92% |
Debt instrument due date | Jun. 24, 2027 | Jun. 24, 2027 |
Debentures [Member] | Medium-term notes, 6.76% series, due 2027 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument interest rate | 6.76% | 6.76% |
Debt instrument due date | Sep. 24, 2027 | Sep. 24, 2027 |
IDRBs [Member] | Tax-exempt Series A, due 2028 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument due date | Dec. 1, 2028 | Dec. 1, 2028 |
IDRBs [Member] | 2003 Series A, due 2038 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument due date | Mar. 1, 2038 | Mar. 1, 2038 |
IDRBs [Member] | 2008 Series A, due 2038 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument due date | Mar. 1, 2038 | Mar. 1, 2038 |
IDRBs [Member] | Market Value [Member] | 2009 Series A, due 2039 [Member] | ||
Debt Instrument [Line Items] | ||
Debt instrument due date | Dec. 1, 2039 | Dec. 1, 2039 |
Long-Term Debt - Additional Inf
Long-Term Debt - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 12 Months Ended | ||||||
Nov. 30, 2017 | Jul. 31, 2017 | Mar. 31, 2017 | Jan. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2017 | Nov. 29, 2017 | Oct. 31, 2017 | Dec. 31, 2016 | |
Debt Instrument [Line Items] | |||||||||
Minimum current borrowing usage | $ 0 | ||||||||
Maximum current borrowing usage | $ 348,000,000 | ||||||||
Debt instrument covenant description | Certain debt instruments contain securities ratings covenants that, if set in motion, would increase financing costs. Certain debt instruments also have leverage ratio caps and minimum net worth requirements. At December 31, 2017, the Company is in compliance with all of its covenants. | ||||||||
Issuance of additional debt | $ 2,100,000,000 | ||||||||
Minimum net worth | $ 1,000,000,000 | ||||||||
Centuri Construction Group Inc [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Debt instrument covenant description | Certain Centuri debt instruments have leverage ratio caps and fixed charge ratio coverage requirements. At December 31, 2017, Centuri is in compliance with all of its covenants | ||||||||
Issuance of additional debt | $ 69,000,000 | ||||||||
Equity cushion relating to minimum fixed charge ratio coverage requirement | $ 28,000,000 | ||||||||
Dividend restriction Maximum | 50.00% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Minimum current borrowing usage | $ 51,000,000 | ||||||||
Maximum current borrowing usage | $ 104,000,000 | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | $ 450,000,000 | 450,000,000 | $ 450,000,000 | $ 300,000,000 | $ 300,000,000 | ||||
Credit facility expiration date | Nov. 30, 2022 | ||||||||
Debt secured by assets | 614,000,000 | $ 614,000,000 | |||||||
Secured Revolving Credit and Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | Minimum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Commitment fee | 0.15% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | Maximum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Commitment fee | 0.35% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | LIBOR [Member] | Minimum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 1.00% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | LIBOR [Member] | Maximum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 104.00% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Canadian Dealer Offered Rate [Member] | Minimum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 1.00% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Canadian Dealer Offered Rate [Member] | Maximum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 2.25% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Base Rate [Member] | Minimum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 0.00% | ||||||||
Secured Revolving Credit and Term Loan Facility [Member] | Base Rate [Member] | Maximum [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 1.25% | ||||||||
Centuri Secured Revolving Credit Facility [Member] | Secured Revolving Credit and Term Loan Facility [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Borrowings outstanding under facility | 256,000,000 | $ 256,000,000 | |||||||
Effective interest rate | 3.54% | ||||||||
Southwest Gas Credit Facility [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | 400,000,000 | ||||||||
Line of credit designated as long term debt | 150,000,000 | ||||||||
Line of credit designated for working capital purposes | 250,000,000 | ||||||||
Credit facility expiration date | Mar. 1, 2022 | ||||||||
Effective interest rate | 2.34% | ||||||||
Southwest Gas Credit Facility [Member] | Long-term Debt [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Borrowings outstanding under facility | 150,000,000 | $ 150,000,000 | |||||||
Southwest Gas Credit Facility [Member] | Short Term Credit Facility [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Borrowings outstanding under facility | 191,000,000 | $ 191,000,000 | $ 0 | ||||||
Southwest Gas Credit Facility [Member] | LIBOR [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 1.00% | ||||||||
Southwest Gas Credit Facility [Member] | Alternative Base Rate [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Applicable margin | 0.00% | ||||||||
Southwest Gas Credit Facility [Member] | Before Amendment [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | $ 300,000,000 | ||||||||
Previous credit facility expiration date | Mar. 1, 2021 | ||||||||
Commercial Paper Program [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | 50,000,000 | $ 50,000,000 | |||||||
Borrowings outstanding under facility | $ 50,000,000 | $ 50,000,000 | |||||||
Medium-term notes, 7.59% series, due 2017 [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Repayments of medium term notes | $ 25,000,000 | ||||||||
Debt instrument interest rate | 7.59% | ||||||||
Line of Credit [Member] | Secured Revolving Credit and Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | $ 250,000,000 | ||||||||
Centuri Term Loan Facility [Member] | Secured Revolving Credit and Term Loan Facility [Member] | Centuri Construction Group Inc [Member] | |||||||||
Debt Instrument [Line Items] | |||||||||
Credit facility maximum borrowing capacity | $ 200,000,000 | $ 150,000,000 |
Long-Term Debt - Summary of Eff
Long-Term Debt - Summary of Effective Interest Rates on Variable-Rate IDRBs (Detail) | Dec. 31, 2017 | Dec. 31, 2016 |
2003 Series A, due 2038 [Member] | ||
Debt Instrument [Line Items] | ||
Effective interest rates | 2.44% | 1.47% |
2008 Series A, due 2038 [Member] | ||
Debt Instrument [Line Items] | ||
Effective interest rates | 2.59% | 1.53% |
2009 Series A, due 2039 [Member] | ||
Debt Instrument [Line Items] | ||
Effective interest rates | 2.40% | 1.43% |
Tax-exempt Series A, due 2028 [Member] | ||
Debt Instrument [Line Items] | ||
Effective interest rates | 2.56% | 1.51% |
Long-Term Debt - Estimated Matu
Long-Term Debt - Estimated Maturities of Long-Term Debt (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Debt Instrument [Line Items] | |
2,018 | $ 25,346 |
2,019 | 26,707 |
2,020 | 152,955 |
2,021 | 25,140 |
2,022 | 619,577 |
Southwest Gas Corporation [Member] | |
Debt Instrument [Line Items] | |
2,020 | 125,000 |
2,022 | 425,000 |
Centuri Construction Group Inc [Member] | |
Debt Instrument [Line Items] | |
2,018 | 25,346 |
2,019 | 26,707 |
2,020 | 27,955 |
2,021 | 25,140 |
2,022 | $ 194,577 |
Short-Term Debt - Additional In
Short-Term Debt - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | |
Mar. 31, 2017 | Dec. 31, 2017 | Sep. 30, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | |
Short-term Debt [Line Items] | |||||
Short term borrowings outstanding | $ 214,500,000 | $ 214,500,000 | |||
Maximum current borrowing usage | $ 348,000,000 | ||||
Southwest Gas Credit Facility [Member] | |||||
Short-term Debt [Line Items] | |||||
Credit facility maximum borrowing capacity | $ 400,000,000 | ||||
Credit facility expiration date | Mar. 1, 2022 | ||||
Line of credit designated for working capital purposes | 250,000,000 | ||||
Southwest Gas Credit Facility [Member] | Alternative Base Rate [Member] | |||||
Short-term Debt [Line Items] | |||||
Applicable margin | 0.00% | ||||
Southwest Gas Credit Facility [Member] | LIBOR [Member] | |||||
Short-term Debt [Line Items] | |||||
Applicable margin | 1.00% | ||||
Short-term Debt [Member] | Southwest Gas Credit Facility [Member] | |||||
Short-term Debt [Line Items] | |||||
Credit facility maximum borrowing capacity | $ 100,000,000 | ||||
Credit facility expiration date | Mar. 31, 2022 | ||||
Effective interest rate | 3.20% | 3.20% | |||
Borrowings outstanding under facility | $ 191,000,000 | $ 191,000,000 | $ 0 | ||
Short-term Debt [Member] | Southwest Gas Credit Facility [Member] | Credit Facility [Member] | |||||
Short-term Debt [Line Items] | |||||
Short term borrowings outstanding | $ 23,500,000 | $ 23,500,000 | |||
Maximum current borrowing usage | $ 28,500,000 | ||||
Short-term Debt [Member] | Southwest Gas Credit Facility [Member] | Alternative Base Rate [Member] | |||||
Short-term Debt [Line Items] | |||||
Applicable margin | 0.125% | ||||
Short-term Debt [Member] | Southwest Gas Credit Facility [Member] | LIBOR [Member] | |||||
Short-term Debt [Line Items] | |||||
Applicable margin | 1.125% |
CommitmentAndContingencies - Ad
CommitmentAndContingencies - Additional Information (Detail) $ in Millions | Dec. 31, 2017USD ($) |
Commitments and Contingencies Disclosure [Abstract] | |
Self-insured retention amount associated with general liability claims | $ 1 |
Additional self-insured retention amount of general liability | $ 4 |
Pension and Other Postretirem85
Pension and Other Postretirement Benefits - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | ||
Maximum contribution of employer | 3.50% | |
Deferment of annual cash compensation | 100.00% | |
Matching contribution of employer | 3.50% | |
Deferred compensation payments on retirement | Upon retirement, payments of compensation deferred, plus interest, are made in equal monthly installments over 10, 15, or 20 years, as elected by the participant | |
Additional Deferred Compensation Payment Options, period of payment, years | 5 years | |
Deferred compensation, percentage of multiple interest rate | 150.00% | |
Increments of changes to the discount rate, basis points | 0.25% | 0.75% |
Future estimated funding amount | $ 47 | |
Qualified Retirement Plan [Member] | ||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | ||
Future estimated funding amount | $ 44 | |
Maximum [Member] | ||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | ||
Per capita cost of covered health care benefits medical rate trend assumption | 6.50% | |
Minimum [Member] | ||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | ||
Per capita cost of covered health care benefits medical rate trend assumption | 4.50% |
Pension and Other Postretirem86
Pension and Other Postretirement Benefits - Cost of Retirement Plan (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract] | |||
Employee Investment Plan cost | $ 5,112 | $ 4,976 | $ 5,072 |
Pension and Other Postretirem87
Pension and Other Postretirement Benefits - Schedule of Assumptions Used (Detail) | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract] | ||
Discount rate | 3.75% | 4.50% |
Weighted-average rate of compensation increase | 3.25% | 3.25% |
Asset return assumption | 7.00% | 7.00% |
Pension and Other Postretirem88
Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in Balance Sheet and Income Statement (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Qualified Retirement Plan [Member] | |||
Change in benefit obligations | |||
Change in benefit obligations Benefit obligation for service rendered to date at beginning of year (PBO/PBO/APBO) | $ 1,048,353 | $ 1,044,817 | |
Service cost | 23,392 | 22,833 | $ 25,123 |
Interest cost | 46,083 | 46,027 | 44,229 |
Actuarial loss (gain) | 133,017 | 8,550 | |
Benefits paid | (47,361) | (73,874) | |
Benefit obligation at end of year (PBO/PBO/APBO) | 1,203,484 | 1,048,353 | 1,044,817 |
Change in plan assets | |||
Market value of plan assets, beginning balance | 738,962 | 736,880 | |
Actual return on plan assets | 144,064 | 39,956 | |
Employer contributions | 36,000 | 36,000 | |
Benefits paid | (47,361) | (73,874) | |
Market value of plan assets, ending balance | 871,665 | 738,962 | 736,880 |
Funded status at year end | $ (331,819) | $ (309,391) | |
Weighted-average assumptions (benefit obligation) | |||
Discount rate | 3.75% | 4.50% | |
Weighted-average rate of compensation increase | 3.25% | 3.25% | |
SERP [Member] | |||
Change in benefit obligations | |||
Change in benefit obligations Benefit obligation for service rendered to date at beginning of year (PBO/PBO/APBO) | $ 43,311 | $ 42,720 | |
Service cost | 309 | 331 | 320 |
Interest cost | 1,883 | 1,859 | 1,695 |
Actuarial loss (gain) | 3,334 | 1,347 | |
Benefits paid | (3,110) | (2,946) | |
Benefit obligation at end of year (PBO/PBO/APBO) | 45,727 | 43,311 | 42,720 |
Change in plan assets | |||
Employer contributions | 3,110 | 2,946 | |
Benefits paid | (3,110) | (2,946) | |
Funded status at year end | $ (45,727) | $ (43,311) | |
Weighted-average assumptions (benefit obligation) | |||
Discount rate | 3.75% | 4.50% | |
Weighted-average rate of compensation increase | 3.25% | 3.25% | |
PBOP [Member] | |||
Change in benefit obligations | |||
Change in benefit obligations Benefit obligation for service rendered to date at beginning of year (PBO/PBO/APBO) | $ 73,865 | $ 72,632 | |
Service cost | 1,468 | 1,499 | 1,641 |
Interest cost | 3,232 | 3,180 | 2,999 |
Actuarial loss (gain) | (71) | (2,060) | |
Benefits paid | (3,172) | (1,386) | |
Benefit obligation at end of year (PBO/PBO/APBO) | 75,322 | 73,865 | 72,632 |
Change in plan assets | |||
Market value of plan assets, beginning balance | 48,113 | 43,584 | |
Actual return on plan assets | 7,742 | 4,818 | |
Benefits paid | (1,247) | (289) | |
Market value of plan assets, ending balance | 54,608 | 48,113 | $ 43,584 |
Funded status at year end | $ (20,714) | $ (25,752) | |
Weighted-average assumptions (benefit obligation) | |||
Discount rate | 3.75% | 4.50% |
Pension and Other Postretirem89
Pension and Other Postretirement Benefits - Schedule of Accumulated Benefit Obligation (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Qualified Retirement Plan [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Accumulated benefit obligation | $ 1,088,203 | $ 939,002 |
SERP [Member] | ||
Defined Benefit Plan Disclosure [Line Items] | ||
Accumulated benefit obligation | $ 44,343 | $ 40,852 |
Pension and Other Postretirem90
Pension and Other Postretirement Benefits - Schedule of Expected Benefit Payments (Detail) $ in Millions | Dec. 31, 2017USD ($) |
Pension [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
2,018 | $ 51 |
2,019 | 52.2 |
2,020 | 53.6 |
2,021 | 55.1 |
2,022 | 56.6 |
2023-2027 | 308.3 |
SERP [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
2,018 | 3 |
2,019 | 3 |
2,020 | 3 |
2,021 | 2.9 |
2,022 | 2.9 |
2023-2027 | 14.1 |
PBOP [Member] | |
Defined Benefit Plan Disclosure [Line Items] | |
2,018 | 4.1 |
2,019 | 4.2 |
2,020 | 4.3 |
2,021 | 4.3 |
2,022 | 4.2 |
2023-2027 | $ 19.6 |
Pension and Other Postretirem91
Pension and Other Postretirement Benefits - Schedule of Net Periodic Benefit Cost and Weighted-Average Assumptions (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Defined Benefit Plan Disclosure [Line Items] | |||
Net periodic benefit cost | $ 44,593 | $ 44,423 | $ 50,451 |
Weighted-average assumptions (net benefit cost) | |||
Discount rate | 3.75% | 4.50% | |
Expected return on plan assets | 7.00% | 7.00% | |
Weighted-average rate of compensation increase | 3.25% | 3.25% | |
Qualified Retirement Plan [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Service cost | $ 23,392 | $ 22,833 | 25,123 |
Interest cost | 46,083 | 46,027 | 44,229 |
Expected return on plan assets | (55,196) | (56,558) | (57,808) |
Amortization of net actuarial loss | 24,004 | 25,266 | 32,743 |
Net periodic benefit cost | $ 38,283 | $ 37,568 | $ 44,287 |
Weighted-average assumptions (net benefit cost) | |||
Discount rate | 4.50% | 4.50% | 4.25% |
Expected return on plan assets | 7.00% | 7.25% | 7.75% |
Weighted-average rate of compensation increase | 3.25% | 3.25% | 2.75% |
SERP [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Service cost | $ 309 | $ 331 | $ 320 |
Interest cost | 1,883 | 1,859 | 1,695 |
Amortization of net actuarial loss | 1,441 | 1,383 | 1,293 |
Net periodic benefit cost | $ 3,633 | $ 3,573 | $ 3,308 |
Weighted-average assumptions (net benefit cost) | |||
Discount rate | 4.50% | 4.50% | 4.25% |
Weighted-average rate of compensation increase | 3.25% | 3.25% | 2.75% |
PBOP [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Service cost | $ 1,468 | $ 1,499 | $ 1,641 |
Interest cost | 3,232 | 3,180 | 2,999 |
Expected return on plan assets | (3,358) | (3,149) | (3,464) |
Amortization of prior service cost | 1,335 | 1,335 | 1,335 |
Amortization of net actuarial loss | 417 | 345 | |
Net periodic benefit cost | $ 2,677 | $ 3,282 | $ 2,856 |
Weighted-average assumptions (net benefit cost) | |||
Discount rate | 4.50% | 4.50% | 4.25% |
Expected return on plan assets | 7.00% | 7.25% | 7.75% |
Pension and Other Postretirem92
Pension and Other Postretirement Benefits - Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in Net Periodic Benefit Cost and Other Comprehensive Income (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | |||
Net actuarial loss (gain) | $ 43,027 | $ 22,770 | $ 30,519 |
Amortization of prior service cost | (1,335) | (1,335) | (1,335) |
Amortization of net actuarial loss | (25,445) | (27,066) | (34,381) |
Regulatory adjustment | (12,340) | 5,584 | 5,646 |
Recognized in other comprehensive (income) loss | 3,907 | (47) | 449 |
Net periodic benefit costs recognized in net income | 44,593 | 44,423 | 50,451 |
Total of amount recognized in net periodic benefit cost and other comprehensive (income) loss | 48,500 | 44,376 | 50,900 |
Qualified Retirement Plan [Member] | |||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | |||
Net actuarial loss (gain) | 44,149 | 25,153 | 26,949 |
Amortization of net actuarial loss | (24,004) | (25,266) | (32,743) |
Regulatory adjustment | (18,131) | 102 | 5,214 |
Recognized in other comprehensive (income) loss | 2,014 | (11) | (580) |
Net periodic benefit costs recognized in net income | 38,283 | 37,568 | 44,287 |
Total of amount recognized in net periodic benefit cost and other comprehensive (income) loss | 40,297 | 37,557 | 43,707 |
SERP [Member] | |||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | |||
Net actuarial loss (gain) | 3,334 | 1,347 | 2,322 |
Amortization of net actuarial loss | (1,441) | (1,383) | (1,293) |
Recognized in other comprehensive (income) loss | 1,893 | (36) | 1,029 |
Net periodic benefit costs recognized in net income | 3,633 | 3,573 | 3,308 |
Total of amount recognized in net periodic benefit cost and other comprehensive (income) loss | 5,526 | 3,537 | 4,337 |
PBOP [Member] | |||
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] | |||
Net actuarial loss (gain) | (4,456) | (3,730) | 1,248 |
Amortization of prior service cost | (1,335) | (1,335) | (1,335) |
Amortization of net actuarial loss | (417) | (345) | |
Regulatory adjustment | 5,791 | 5,482 | 432 |
Net periodic benefit costs recognized in net income | 2,677 | 3,282 | 2,856 |
Total of amount recognized in net periodic benefit cost and other comprehensive (income) loss | $ 2,677 | $ 3,282 | $ 2,856 |
Pension and Other Postretirem93
Pension and Other Postretirement Benefits - Schedule of Fair Value of Plan Assets (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets, including insurance contracts | $ 926,273 | $ 787,074 | |
Assets at Fair Value [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 923,086 | 783,626 | |
Insurance Company General Account Contracts (Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Contract value of insurance contracts | 3,187 | 3,448 | |
Level 1 - Quoted Prices in Active Markets for Identical Financial Assets [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 27,020 | 24,922 | |
Level 1 - Quoted Prices in Active Markets for Identical Financial Assets [Member] | Mutual Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 27,020 | 24,922 | |
Level 2 - Significant Other Observable Inputs [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 896,066 | 758,704 | |
Level 2 - Significant Other Observable Inputs [Member] | International [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 350,794 | 299,808 | |
Level 2 - Significant Other Observable Inputs [Member] | Large and Medium Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 141,240 | 125,253 | |
Level 2 - Significant Other Observable Inputs [Member] | Small Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 29,855 | 26,763 | |
Level 2 - Significant Other Observable Inputs [Member] | Emerging Markets [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 58,008 | 46,733 | |
Level 2 - Significant Other Observable Inputs [Member] | U S Corporate Bonds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 162,355 | 166,152 | |
Level 2 - Significant Other Observable Inputs [Member] | US Debt Market Long Duration [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 61,851 | 79,781 | |
Level 2 - Significant Other Observable Inputs [Member] | US Treasury Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 86,375 | 8,937 | |
Level 2 - Significant Other Observable Inputs [Member] | Pooled Funds and Mutual Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 5,411 | 5,105 | |
Level 2 - Significant Other Observable Inputs [Member] | Government Fixed Income and Mortgage Backed Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 177 | 172 | |
Qualified Retirement Plan [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 871,665 | 738,962 | $ 736,880 |
Fair value of plan assets, including insurance contracts | 871,665 | 738,962 | |
Qualified Retirement Plan [Member] | Assets at Fair Value [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 868,478 | 735,514 | |
Qualified Retirement Plan [Member] | Insurance Company General Account Contracts (Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Contract value of insurance contracts | 3,187 | 3,448 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 868,478 | 735,514 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | International [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 340,217 | 290,668 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | Large and Medium Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 136,982 | 121,434 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | Small Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 28,955 | 25,947 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | Emerging Markets [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 56,259 | 45,309 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | U S Corporate Bonds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 157,460 | 161,086 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | US Debt Market Long Duration [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 59,986 | 77,349 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | US Treasury Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 83,771 | 8,665 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | Pooled Funds and Mutual Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 4,676 | 4,889 | |
Qualified Retirement Plan [Member] | Level 2 - Significant Other Observable Inputs [Member] | Government Fixed Income and Mortgage Backed Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 172 | 167 | |
PBOP [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 54,608 | 48,113 | $ 43,584 |
Fair value of plan assets, including insurance contracts | 54,608 | 48,112 | |
PBOP [Member] | Assets at Fair Value [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 54,608 | 48,112 | |
PBOP [Member] | Level 1 - Quoted Prices in Active Markets for Identical Financial Assets [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 27,020 | 24,922 | |
PBOP [Member] | Level 1 - Quoted Prices in Active Markets for Identical Financial Assets [Member] | Mutual Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 27,020 | 24,922 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 27,588 | 23,190 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | International [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 10,577 | 9,140 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | Large and Medium Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 4,258 | 3,819 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | Small Capitalization [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 900 | 816 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | Emerging Markets [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 1,749 | 1,424 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | U S Corporate Bonds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 4,895 | 5,066 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | US Debt Market Long Duration [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 1,865 | 2,432 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | US Treasury Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 2,604 | 272 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | Pooled Funds and Mutual Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | 735 | 216 | |
PBOP [Member] | Level 2 - Significant Other Observable Inputs [Member] | Government Fixed Income and Mortgage Backed Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair value of plan assets | $ 5 | $ 5 |
Stock-Based Compensation - Sche
Stock-Based Compensation - Schedule of Stock-Based Plan Compensation Expense, Including Cash Award (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||
Stock-based compensation plan expense, net of related tax benefits | $ 6,751 | $ 7,185 | $ 7,278 |
Stock-based compensation plan related tax benefits | $ 4,137 | $ 4,404 | $ 4,461 |
Stock-Based Compensation - Addi
Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Options, maximum term, years | 10 years | ||
Shares available for issuance | 103,000 | ||
Compensation expense | $ 10,888 | $ 5,456 | $ 2,914 |
Total compensation cost related to nonvested management incentive plan shares, performance shares, and restricted stock/units not yet recognized | $ 4,400 | ||
Management Incentive Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares, granted | 32,000 | ||
Weighted average grant date fair value | $ 85.44 | $ 59.05 | $ 63.09 |
Restricted Stock Units (RSUs) [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares, granted | 106,000 | ||
Weighted average grant date fair value | $ 85.39 | $ 60.39 | $ 63.09 |
Performance Shares [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares, granted | 33,000 | ||
Compensation expense | $ 1,200 | ||
Omnibus Incentive Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Shares available for issuance | 1 | ||
Omnibus Incentive Plan [Member] | Management Incentive Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares, granted | 0 | ||
Omnibus Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Number of shares, granted | 0 |
Stock-Based Compensation - Sc96
Stock-Based Compensation - Schedule of Stock Options Activity (Detail) - $ / shares shares in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||
Number of options, Outstanding at the beginning of the year | 17 | 36 | |
Number of options, Exercised during the year | (17) | (19) | |
Number of options, Forfeited or expired during the year | 0 | 0 | 0 |
Number of options, Outstanding and exercisable at year end | 17 | ||
Weighted-average exercise price, Outstanding at the beginning of the year | $ 31.64 | $ 28.97 | |
Weighted-average exercise price, Exercised during the year | 31.64 | 26.69 | |
Weighted-average exercise price, Forfeited or expired during the year | $ 0 | $ 0 | 0 |
Weighted-average exercise price, Outstanding and exercisable at year end | $ 31.64 |
Stock-Based Compensation - Sc97
Stock-Based Compensation - Schedule of Aggregate Intrinsic Value of Outstanding and Exercisable Options (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2016 | Dec. 31, 2015 | |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||
Outstanding and exercisable | $ 394 | |
Exercised | $ 554 | $ 590 |
Stock-Based Compensation - Summ
Stock-Based Compensation - Summary of Market Prices of Common Stock (Detail) - USD ($) | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 |
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | |||
Market value of Company stock | $ 80.48 | $ 76.62 | $ 55.16 |
Stock-Based Compensation - Sc99
Stock-Based Compensation - Schedule of Nonvested Performance and Restricted Stock Unit Plans (Detail) - $ / shares shares in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Management Incentive Plan [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Nonvested/unissued, Number of Units, at beginning of year | 168 | ||
Nonvested, Number of Units, Granted | 32 | ||
Nonvested, Number of Units, Dividends | 3 | ||
Nonvested, Number of Units, Forfeited or expired | (1) | ||
Nonvested, Number of Units, Vested and issued | (75) | ||
Nonvested/unissued, Number of Units, Ending balance | 127 | 168 | |
Weighted-average grant date fair value, Beginning balance | $ 55.62 | ||
Weighted-average grant date fair value, Granted | 85.44 | $ 59.05 | $ 63.09 |
Weighted-average grant date fair value, Dividends | 0 | ||
Weighted-average grant date fair value, Forfeited or expired | 59.02 | ||
Weighted-average grant date fair value, Vested and issued | 51.93 | ||
Weighted-average grant date fair value, Ending balance | $ 63.98 | $ 55.62 | |
Restricted Stock Units (RSUs) [Member] | |||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Nonvested/unissued, Number of Units, at beginning of year | 262 | ||
Nonvested, Number of Units, Granted | 106 | ||
Nonvested, Number of Units, Dividends | 7 | ||
Nonvested, Number of Units, Forfeited or expired | (1) | ||
Nonvested, Number of Units, Vested and issued | (69) | ||
Nonvested/unissued, Number of Units, Ending balance | 305 | 262 | |
Weighted-average grant date fair value, Beginning balance | $ 46.41 | ||
Weighted-average grant date fair value, Granted | 85.39 | $ 60.39 | $ 63.09 |
Weighted-average grant date fair value, Dividends | 0 | ||
Weighted-average grant date fair value, Forfeited or expired | 69.85 | ||
Weighted-average grant date fair value, Vested and issued | 53.28 | ||
Weighted-average grant date fair value, Ending balance | $ 57.41 | $ 46.41 |
Stock-Based Compensation - S100
Stock-Based Compensation - Schedule of Nonvested Performance and Restricted Stock Unit Plans (Parenthetical) (Detail) | 12 Months Ended |
Dec. 31, 2017shares | |
Performance Shares [Member] | |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
Number of securities granted | 33,000 |
Income Taxes - Additional Infor
Income Taxes - Additional Information (Detail) - USD ($) | 12 Months Ended | |||
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax Disclosure [Line Items] | ||||
Federal income tax rate | 35.00% | 35.00% | 35.00% | |
Foreign [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Operating loss carryforward | $ 54,600,000 | |||
Operating loss carryforward expiration year | 2,038 | |||
Capital Loss Carryforward [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Loss carryforward | $ 278,000,000 | |||
Loss carryforward expiration year | 2,018 | |||
Canada [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Operating loss carryforward | $ 5,200,000 | |||
Operating loss carryforward expiration year | 2,032 | |||
Scenario, Forecast [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Federal income tax rate | 21.00% | |||
Southwest Gas Corporation [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Federal income tax rate | 35.00% | 35.00% | 35.00% | |
Increase in regulatory liabilities | $ 430,000,000 | |||
Decrease in deferred tax liabilities | 450 | |||
Loss carryforward | $ 329,000,000 | |||
Loss carryforward expiration year | 2,038 | |||
Unrecognized tax benefits that, if recognized, would affect the effective tax rate | $ 1,100,000 | |||
Significant increases or decreases in unrecognized tax benefit within the next 12 months | 0 | |||
Tax-related interest income | $ 0 | $ 0 | $ 0 | |
Southwest Gas Corporation [Member] | Minimum [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Amount of benefit being recognized in financial statements upon ultimate settlement, Percentage | 50.00% | |||
Southwest Gas Corporation [Member] | Scenario, Forecast [Member] | ||||
Income Tax Disclosure [Line Items] | ||||
Federal income tax rate | 21.00% |
Income Taxes - Summary of Incom
Income Taxes - Summary of Income Before Taxes and Noncontrolling Interest for Domestic and Foreign Operations (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax [Line Items] | |||
Total income before income taxes | $ 259,030 | $ 231,523 | $ 219,332 |
Foreign [Member] | |||
Income Tax [Line Items] | |||
Total income before income taxes | 12,899 | 12,713 | (2,328) |
United States [Member] | |||
Income Tax [Line Items] | |||
Total income before income taxes | $ 246,131 | $ 218,810 | $ 221,660 |
Income Taxes - Summary of In103
Income Taxes - Summary of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Tax [Line Items] | |||
Discontinued operations | $ 58,236 | $ 67,881 | $ 48,032 |
Current: | |||
Federal | (1,316) | 541 | 21,321 |
State | 2,965 | 5,748 | 9,899 |
Foreign | 5,203 | 4,298 | 650 |
Income tax expense (benefit), Current | 6,852 | 10,587 | 31,870 |
Deferred: | |||
Federal | 58,443 | 68,270 | 51,132 |
State | 1,837 | 140 | (2,574) |
Foreign | (2,044) | (529) | (526) |
Total deferred income tax expense | 58,236 | 67,881 | 48,032 |
Total income tax expense | 65,088 | 78,468 | 79,902 |
Southwest Gas Corporation [Member] | |||
Income Tax [Line Items] | |||
Discontinued operations | 61,397 | 65,769 | 51,337 |
Current: | |||
Federal | 318 | (9,695) | 3,789 |
State | 1,420 | 2,510 | 6,229 |
Income tax expense (benefit), Current | 1,738 | (7,185) | 10,018 |
Deferred: | |||
Federal | 60,662 | 66,037 | 53,657 |
State | 735 | (268) | (2,320) |
Total deferred income tax expense | 61,397 | 65,769 | 51,337 |
Total income tax expense | 63,135 | 58,584 | 61,355 |
Southwest Gas Corporation [Member] | Continuing Operations [Member] | |||
Income Tax [Line Items] | |||
Discontinued operations | 63,135 | 58,584 | 61,355 |
Deferred: | |||
Total deferred income tax expense | $ 63,135 | 58,584 | 61,355 |
Southwest Gas Corporation [Member] | Discontinued Operations [Member] | |||
Income Tax [Line Items] | |||
Discontinued operations | 19,884 | 18,547 | |
Deferred: | |||
Total deferred income tax expense | $ 19,884 | $ 18,547 |
Income Taxes - Significant Comp
Income Taxes - Significant Components of Deferred Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Deferred federal and state: | |||
Total deferred federal and state | $ 58,965 | $ 68,719 | $ 48,893 |
Deferred ITC, net | (729) | (838) | (861) |
Total deferred income tax expense | 58,236 | 67,881 | 48,032 |
Property-related Items [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 44,516 | 76,217 | 65,931 |
Purchased Gas Cost Adjustments [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 8,500 | 361 | (32,993) |
Employee Benefits [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | (2,517) | (1,327) | 623 |
Regulatory Adjustments [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 14,401 | 6,322 | 1,545 |
All Other Deferred [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | (5,935) | (12,854) | 13,787 |
Southwest Gas Corporation [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 62,126 | 66,607 | 52,198 |
Deferred ITC, net | (729) | (838) | (861) |
Total deferred income tax expense | 61,397 | 65,769 | 51,337 |
Southwest Gas Corporation [Member] | Property-related Items [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 49,129 | 72,811 | 68,105 |
Southwest Gas Corporation [Member] | Purchased Gas Cost Adjustments [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 8,500 | 361 | (32,993) |
Southwest Gas Corporation [Member] | Employee Benefits [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | (5,707) | (139) | (4,795) |
Southwest Gas Corporation [Member] | Regulatory Adjustments [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | 14,401 | 6,322 | 1,545 |
Southwest Gas Corporation [Member] | All Other Deferred [Member] | |||
Deferred federal and state: | |||
Total deferred federal and state | $ (4,197) | $ (12,748) | $ 20,336 |
Income Taxes - Reconciliation o
Income Taxes - Reconciliation of U.S Federal Statutory Rate to Consolidated Effective Tax Rate (Detail) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Income Taxes [Line Items] | |||
U.S. federal statutory income tax rate | 35.00% | 35.00% | 35.00% |
Net state taxes | 1.10% | 1.40% | 1.80% |
Property-related items | 0.10% | ||
Tax credits | (0.40%) | (0.40%) | (0.40%) |
Company owned life insurance | (1.60%) | (1.20%) | 0.10% |
Change in U.S. Federal Income Tax Rate | (7.80%) | ||
All other differences | (1.20%) | (0.90%) | (0.20%) |
Consolidated effective income tax rate | 25.10% | 33.90% | 36.40% |
Southwest Gas Corporation [Member] | |||
Income Taxes [Line Items] | |||
U.S. federal statutory income tax rate | 35.00% | 35.00% | 35.00% |
Net state taxes | 0.60% | 0.80% | 1.00% |
Property-related items | 0.10% | ||
Tax credits | (0.40%) | (0.50%) | (0.50%) |
Company owned life insurance | (1.70%) | (1.50%) | |
Change in U.S. Federal Income Tax Rate | (3.60%) | ||
All other differences | (1.20%) | (0.90%) | (0.10%) |
Consolidated effective income tax rate | 28.70% | 32.90% | 35.50% |
Income Taxes - Deferred Tax Ass
Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Deferred tax assets: | ||
Deferred income taxes for future amortization of ITC and excess deferred taxes | $ 98,912 | $ 1,094 |
Employee benefits | 31,323 | 38,231 |
Alternative minimum tax credit | 4,390 | 4,827 |
Net operating losses and credits | 11,460 | 1,204 |
Interest rate swap | 3,037 | 6,080 |
Other | 13,870 | 18,415 |
Valuation allowance | (728) | (495) |
Deferred tax assets, total | 162,264 | 69,356 |
Deferred tax liabilities: | ||
Property-related items, including accelerated depreciation | 598,371 | 872,136 |
Regulatory balancing accounts | 6,067 | 1,104 |
Unamortized ITC | 981 | 1,710 |
Debt-related costs | 3,380 | 5,712 |
Intangibles | 7,656 | 8,803 |
Other | 21,289 | 19,256 |
Deferred tax liabilities, total | 637,744 | 908,721 |
Net deferred tax liabilities | 475,480 | 839,365 |
Southwest Gas Corporation [Member] | ||
Deferred tax assets: | ||
Deferred income taxes for future amortization of ITC and excess deferred taxes | 98,912 | 1,094 |
Employee benefits | 18,707 | 22,426 |
Alternative minimum tax credit | 4,390 | 4,827 |
Net operating losses and credits | 10,070 | |
Interest rate swap | 3,037 | 6,080 |
Other | 8,820 | 15,204 |
Valuation allowance | (58) | (223) |
Deferred tax assets, total | 143,878 | 49,408 |
Deferred tax liabilities: | ||
Property-related items, including accelerated depreciation | 561,493 | 830,758 |
Regulatory balancing accounts | 6,067 | 1,104 |
Unamortized ITC | 981 | 1,710 |
Debt-related costs | 3,380 | 5,712 |
Other | 17,200 | 16,233 |
Deferred tax liabilities, total | 589,121 | 855,517 |
Net deferred tax liabilities before discontinued operations | 445,243 | 806,109 |
Discontinued operations | 33,256 | |
Net deferred tax liabilities | $ 445,243 | $ 839,365 |
Income Taxes - Reconciliatio107
Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Income Tax [Line Items] | ||
Unrecognized tax benefits at beginning of year | $ 1,231 | $ 296 |
Gross increases - tax positions in prior period | 100 | 897 |
Gross decreases - tax positions in prior period | 0 | 0 |
Gross increases - current period tax positions | 99 | 38 |
Gross decreases - current period tax positions | 0 | 0 |
Settlements | 0 | 0 |
Lapse in statute of limitations | 0 | 0 |
Unrecognized tax benefits at end of year | 1,430 | 1,231 |
Southwest Gas Corporation [Member] | ||
Income Tax [Line Items] | ||
Unrecognized tax benefits at beginning of year | 903 | |
Gross increases - tax positions in prior period | 67 | 865 |
Gross decreases - tax positions in prior period | 0 | 0 |
Gross increases - current period tax positions | 99 | 38 |
Gross decreases - current period tax positions | 0 | 0 |
Settlements | 0 | 0 |
Lapse in statute of limitations | 0 | 0 |
Unrecognized tax benefits at end of year | $ 1,069 | $ 903 |
Income Taxes - Summary of In108
Income Taxes - Summary of Income Before Taxes for Continuing and Discontinued Operations (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] | |||
Income before income taxes | $ 259,030 | $ 231,523 | $ 219,332 |
Total income before income taxes | 259,030 | 231,523 | 219,332 |
Southwest Gas Corporation [Member] | |||
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] | |||
Income before income taxes | 219,953 | 178,007 | 172,980 |
Income from discontinued operations before income taxes | 53,516 | 46,352 | |
Total income before income taxes | $ 219,953 | $ 231,523 | $ 219,332 |
Derivatives and Fair Value M109
Derivatives and Fair Value Measurements - Additional Information (Detail) - USD ($) | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Derivative [Line Items] | |||
Gains (losses) recognized in income or other comprehensive income for derivative designated cash flow hedges | $ 2,073,000 | $ 2,075,000 | $ 2,073,000 |
Derivative instrument loss at settlement amortization period | 10 years | ||
Cash Flow Hedging [Member] | |||
Derivative [Line Items] | |||
Gains (losses) recognized in income or other comprehensive income for derivative designated cash flow hedges | $ 0 | ||
Minimum [Member] | |||
Derivative [Line Items] | |||
Maturities of natural gas swaps | Jan. 31, 2018 | ||
Maximum [Member] | |||
Derivative [Line Items] | |||
Maturities of natural gas swaps | Oct. 31, 2019 | ||
Arizona [Member] | |||
Derivative [Line Items] | |||
Natural gas portfolios, maximum % rate | 25.00% | ||
California [Member] | |||
Derivative [Line Items] | |||
Natural gas portfolios, maximum % rate | 25.00% |
Derivatives and Fair Value M110
Derivatives and Fair Value Measurements - Notional Amounts under Swaps Contracts (Detail) - MMBTU | Dec. 31, 2017 | Dec. 31, 2016 |
Offsetting [Abstract] | ||
Contract notional amounts | 10,929,000 | 10,543,000 |
Derivatives and Fair Value M111
Derivatives and Fair Value Measurements - Amount of Gain or Losses Recognized in Income on Derivatives (Detail) - Cash Flow Hedging [Member] - Net Cost of Gas Sold [Member] - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Derivative Instruments, Gain (Loss) [Line Items] | |||
Amount of gain or (loss) recognized in income on derivative | $ (11,572) | $ 5,006 | $ (7,598) |
Regulatory Deferral Accounting Treatment [Member] | |||
Derivative Instruments, Gain (Loss) [Line Items] | |||
Amount of gain or (loss) recognized in income on derivative | $ 11,572 | $ (5,006) | $ 7,598 |
Derivatives and Fair Value M112
Derivatives and Fair Value Measurements - Fair Values of Swaps in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Derivatives, Fair Value [Line Items] | ||
Asset derivatives not designated as hedging instruments | $ 30 | $ 4,450 |
Liability derivatives not designated as hedging instruments | (5,810) | (73) |
Net total not designated as hedging instruments | (5,780) | 4,377 |
Swaps [Member] | Deferred Charges and Other Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Asset derivatives not designated as hedging instruments | 899 | |
Liability derivatives not designated as hedging instruments | (54) | |
Net total not designated as hedging instruments | 845 | |
Swaps [Member] | Prepaids and Other Current Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Asset derivatives not designated as hedging instruments | 3,551 | |
Liability derivatives not designated as hedging instruments | (19) | |
Net total not designated as hedging instruments | $ 3,532 | |
Swaps [Member] | Other Current Liabilities [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Asset derivatives not designated as hedging instruments | 11 | |
Liability derivatives not designated as hedging instruments | (4,468) | |
Net total not designated as hedging instruments | (4,457) | |
Swaps [Member] | Other Deferred Credits [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Asset derivatives not designated as hedging instruments | 19 | |
Liability derivatives not designated as hedging instruments | (1,342) | |
Net total not designated as hedging instruments | $ (1,323) |
Derivatives and Fair Value M113
Derivatives and Fair Value Measurements - Paid to and Received from Counterparties for Settlements of Matured Swaps (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Derivative Instruments and Hedging Activities Disclosure [Abstract] | |||
Paid to counterparties | $ 3,100 | $ 5,583 | $ 7,537 |
Received from counterparties | $ 1,685 | $ 726 |
Derivatives and Fair Value M114
Derivatives and Fair Value Measurements - Regulatory Assets/Liabilities Offsetting Derivatives at Fair Value in Condensed Consolidated Balance Sheets (Detail) - Swaps [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Prepaids and Other Current Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Net Total | $ 4,457 | |
Deferred Charges and Other Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Net Total | $ 1,323 | |
Other Deferred Credits [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Net Total | $ (845) | |
Other Current Liabilities [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Net Total | $ (3,532) |
Derivatives and Fair Value M115
Derivatives and Fair Value Measurements - Summary of Financial Assets and Liabilities at Fair Value (Detail) - Level 2 - Significant Other Observable Inputs [Member] - Swaps [Member] - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Derivatives, Fair Value [Line Items] | ||
Net Assets (Liabilities) | $ (5,780) | $ 4,377 |
Prepaids and Other Current Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Derivative Assets | 3,532 | |
Deferred Charges and Other Assets [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Derivative Assets | $ 845 | |
Other Current Liabilities [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Derivative Liabilities | (4,457) | |
Other Deferred Credits [Member] | ||
Derivatives, Fair Value [Line Items] | ||
Derivative Liabilities | $ (1,323) |
Segment Information - Additiona
Segment Information - Additional Information (Detail) | 12 Months Ended |
Dec. 31, 2017 | |
Net Assets, Geographic Area [Member] | Geographic Concentration Risk [Member] | United States [Member] | Minimum [Member] | |
Segment Reporting Information [Line Items] | |
Long-lived assets | 99.00% |
Segment Information - Accounts
Segment Information - Accounts Receivable for Services (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016 |
Centuri Construction Group Inc [Member] | ||
Segment Reporting Information [Line Items] | ||
Accounts receivable for Centuri services | $ 12,987 | $ 10,585 |
Segment Information - Schedule
Segment Information - Schedule of Revenues by Geographic Area (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Segment Reporting Information [Line Items] | |||||||||||||||
Total Revenues | $ 740,433 | $ 593,153 | $ 560,469 | $ 654,737 | $ 641,525 | $ 539,969 | $ 547,748 | $ 731,248 | $ 685,405 | $ 505,396 | $ 538,604 | $ 734,220 | $ 2,548,792 | $ 2,460,490 | $ 2,463,625 |
United States [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Total Revenues | 2,345,134 | 2,256,600 | 2,289,133 | ||||||||||||
Canada [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Total Revenues | $ 203,658 | $ 203,890 | $ 174,492 |
Segment Information - Schedu119
Segment Information - Schedule of Segment Reporting Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | $ 2,451,633 | $ 2,362,369 | $ 2,359,509 | ||||||||||||
Interest revenue | 2,787 | 1,849 | 2,173 | ||||||||||||
Interest expense | 78,064 | 73,660 | 71,879 | ||||||||||||
Depreciation and amortization | 250,951 | 289,132 | 270,111 | ||||||||||||
Income tax expense | 65,088 | 78,468 | 79,902 | ||||||||||||
NetIncomeLoss | $ 96,465 | $ 10,204 | $ 17,864 | $ 69,308 | $ 65,180 | $ 2,472 | $ 8,943 | $ 75,446 | $ 66,119 | $ (4,734) | $ 4,949 | $ 71,983 | 193,841 | 152,041 | 138,317 |
Segment assets | 6,237,066 | 5,581,126 | 5,358,685 | 6,237,066 | 5,581,126 | 5,358,685 | |||||||||
Capital expenditures | 623,649 | 529,531 | 488,000 | ||||||||||||
Intersegment revenues [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 97,159 | 98,121 | 104,116 | ||||||||||||
Operating Segments [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 2,548,792 | 2,460,490 | 2,463,625 | ||||||||||||
Natural Gas Operations [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 1,302,308 | 1,321,412 | 1,454,639 | ||||||||||||
Interest revenue | 2,784 | 1,848 | 1,754 | ||||||||||||
Interest expense | 69,733 | 66,997 | 64,095 | ||||||||||||
Depreciation and amortization | 201,922 | 233,463 | 213,455 | ||||||||||||
Income tax expense | 63,135 | 58,584 | 61,355 | ||||||||||||
NetIncomeLoss | 156,818 | 119,423 | 111,625 | ||||||||||||
Segment assets | 5,482,669 | 5,001,756 | 4,822,845 | 5,482,669 | 5,001,756 | 4,822,845 | |||||||||
Capital expenditures | 560,448 | 457,120 | 438,289 | ||||||||||||
Natural Gas Operations [Member] | Operating Segments [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 1,302,308 | 1,321,412 | 1,454,639 | ||||||||||||
Construction Services [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 1,149,325 | 1,040,957 | 904,870 | ||||||||||||
Interest revenue | 3 | 1 | 419 | ||||||||||||
Interest expense | 7,986 | 6,663 | 7,784 | ||||||||||||
Depreciation and amortization | 49,029 | 55,669 | 56,656 | ||||||||||||
Income tax expense | 2,390 | 19,884 | 18,547 | ||||||||||||
NetIncomeLoss | 38,360 | 32,618 | 26,692 | ||||||||||||
Segment assets | 752,496 | $ 579,370 | $ 535,840 | 752,496 | 579,370 | 535,840 | |||||||||
Capital expenditures | 63,201 | 72,411 | 49,711 | ||||||||||||
Construction Services [Member] | Intersegment revenues [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 97,159 | 98,121 | 104,116 | ||||||||||||
Construction Services [Member] | Operating Segments [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Revenues | 1,246,484 | $ 1,139,078 | $ 1,008,986 | ||||||||||||
Other [Member] | |||||||||||||||
Segment Reporting Information [Line Items] | |||||||||||||||
Interest expense | 345 | ||||||||||||||
Income tax expense | (437) | ||||||||||||||
NetIncomeLoss | (1,337) | ||||||||||||||
Segment assets | $ 1,901 | $ 1,901 |
Quarterly Financial Data - Sche
Quarterly Financial Data - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Schedule Of Quarterly Financial Information [Line Items] | |||||||||||||||
Operating revenues | $ 740,433 | $ 593,153 | $ 560,469 | $ 654,737 | $ 641,525 | $ 539,969 | $ 547,748 | $ 731,248 | $ 685,405 | $ 505,396 | $ 538,604 | $ 734,220 | $ 2,548,792 | $ 2,460,490 | $ 2,463,625 |
Operating income | 130,668 | 30,132 | 43,408 | 119,492 | 117,963 | 15,539 | 28,116 | 134,096 | 117,586 | 16,143 | 25,047 | 129,556 | 323,700 | 295,714 | 288,332 |
Net Income | 96,396 | 10,420 | 18,121 | 69,005 | 65,694 | 2,907 | 9,099 | 75,355 | 66,698 | (4,210) | 5,063 | 71,879 | 193,942 | 153,055 | 139,430 |
Operating revenues | 740,433 | 593,153 | 560,469 | 654,737 | 641,525 | 539,969 | 547,748 | 731,248 | 685,405 | 505,396 | 538,604 | 734,220 | 2,548,792 | 2,460,490 | 2,463,625 |
Operating income | 130,668 | 30,132 | 43,408 | 119,492 | 117,963 | 15,539 | 28,116 | 134,096 | 117,586 | 16,143 | 25,047 | 129,556 | 323,700 | 295,714 | 288,332 |
Continuing operations | $ 96,465 | $ 10,204 | $ 17,864 | $ 69,308 | $ 65,180 | $ 2,472 | $ 8,943 | $ 75,446 | $ 66,119 | $ (4,734) | $ 4,949 | $ 71,983 | $ 193,841 | $ 152,041 | $ 138,317 |
Basic earnings per common share (1) | $ 2 | $ 0.21 | $ 0.38 | $ 1.46 | $ 1.37 | $ 0.05 | $ 0.19 | $ 1.59 | $ 1.40 | $ (0.10) | $ 0.11 | $ 1.54 | $ 4.04 | $ 3.20 | $ 2.94 |
Diluted earnings per common share (1) | $ 2 | $ 0.21 | $ 0.37 | $ 1.45 | $ 1.36 | $ 0.05 | $ 0.19 | $ 1.58 | $ 1.38 | $ (0.10) | $ 0.10 | $ 1.53 | $ 4.04 | $ 3.18 | $ 2.92 |
Net income (loss) | $ 96,465 | $ 10,204 | $ 17,864 | $ 69,308 | $ 65,180 | $ 2,472 | $ 8,943 | $ 75,446 | $ 66,119 | $ (4,734) | $ 4,949 | $ 71,983 | $ 193,841 | $ 152,041 | $ 138,317 |
Basic earnings per common share (1) | $ 2 | $ 0.21 | $ 0.38 | $ 1.46 | $ 1.37 | $ 0.05 | $ 0.19 | $ 1.59 | $ 1.40 | $ (0.10) | $ 0.11 | $ 1.54 | $ 4.04 | $ 3.20 | $ 2.94 |
Diluted earnings per common share (1) | $ 2 | $ 0.21 | $ 0.37 | $ 1.45 | $ 1.36 | $ 0.05 | $ 0.19 | $ 1.58 | $ 1.38 | $ (0.10) | $ 0.10 | $ 1.53 | $ 4.04 | $ 3.18 | $ 2.92 |
Southwest Gas Corporation [Member] | |||||||||||||||
Schedule Of Quarterly Financial Information [Line Items] | |||||||||||||||
Operating revenues | $ 641,525 | $ 539,969 | $ 547,748 | $ 731,248 | $ 685,405 | $ 505,396 | $ 538,604 | $ 734,220 | |||||||
Operating income | 117,963 | 15,539 | 28,116 | 134,096 | 117,586 | 16,143 | 25,047 | 129,556 | $ 276,650 | $ 236,728 | $ 234,783 | ||||
Net Income | 156,818 | 153,055 | 139,430 | ||||||||||||
Operating revenues | 641,525 | 539,969 | 547,748 | 731,248 | 685,405 | 505,396 | 538,604 | 734,220 | |||||||
Operating income | 117,963 | 15,539 | 28,116 | 134,096 | 117,586 | 16,143 | 25,047 | 129,556 | 276,650 | 236,728 | 234,783 | ||||
Continuing operations | 65,180 | 2,472 | 8,943 | 75,446 | 66,119 | (4,734) | 4,949 | 71,983 | 156,818 | 152,041 | 138,317 | ||||
Net income (loss) | 65,180 | 2,472 | 8,943 | 75,446 | 66,119 | (4,734) | 4,949 | 71,983 | $ 156,818 | $ 152,041 | $ 138,317 | ||||
Southwest Gas Corporation [Member] | Continuing Operations [Member] | |||||||||||||||
Schedule Of Quarterly Financial Information [Line Items] | |||||||||||||||
Operating revenues | 340,485 | 200,179 | 255,648 | 525,100 | 395,461 | 219,420 | 286,643 | 553,115 | |||||||
Operating income | 95,745 | (10,231) | 15,269 | 135,945 | 93,928 | (9,274) | 12,958 | 137,171 | |||||||
Operating revenues | 340,485 | 200,179 | 255,648 | 525,100 | 395,461 | 219,420 | 286,643 | 553,115 | |||||||
Operating income | 95,745 | (10,231) | 15,269 | 135,945 | 93,928 | (9,274) | 12,958 | 137,171 | |||||||
Continuing operations | 51,887 | (12,405) | 2,358 | 77,583 | 52,300 | (18,939) | (657) | 78,921 | |||||||
Net income (loss) | 51,887 | (12,405) | 2,358 | 77,583 | 52,300 | (18,939) | (657) | 78,921 | |||||||
Southwest Gas Corporation [Member] | Discontinued Operations [Member] | |||||||||||||||
Schedule Of Quarterly Financial Information [Line Items] | |||||||||||||||
Operating revenues | 301,040 | 339,790 | 292,100 | 206,148 | 289,944 | 285,976 | 251,961 | 181,105 | |||||||
Operating income | 22,218 | 25,770 | 12,847 | (1,849) | 23,658 | 25,417 | 12,089 | (7,615) | |||||||
Operating revenues | 301,040 | 339,790 | 292,100 | 206,148 | 289,944 | 285,976 | 251,961 | 181,105 | |||||||
Operating income | 22,218 | 25,770 | 12,847 | (1,849) | 23,658 | 25,417 | 12,089 | (7,615) | |||||||
Continuing operations | 13,293 | 14,877 | 6,585 | (2,137) | 13,819 | 14,205 | 5,606 | (6,938) | |||||||
Net income (loss) | $ 13,293 | $ 14,877 | $ 6,585 | $ (2,137) | $ 13,819 | $ 14,205 | $ 5,606 | $ (6,938) | |||||||
Southwest Gas Corporation [Member] | |||||||||||||||
Schedule Of Quarterly Financial Information [Line Items] | |||||||||||||||
Operating revenues | $ 366,485 | $ 213,059 | $ 260,162 | $ 462,602 | |||||||||||
Operating income | 113,029 | 5,065 | 27,489 | 131,067 | |||||||||||
Net Income | 74,382 | (4,024) | 9,522 | 76,938 | |||||||||||
Operating revenues | 366,485 | 213,059 | 260,162 | 462,602 | |||||||||||
Operating income | $ 113,029 | $ 5,065 | $ 27,489 | $ 131,067 |
Construction Services Redeemabl
Construction Services Redeemable Noncontrolling Interest - Additional Information (Detail) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended |
Aug. 31, 2017 | Dec. 31, 2017 | |
Previous Owners [Member] | ||
Noncontrolling Interest [Line Items] | ||
Purchase price of the previous owners' equity interest in Centuri | $ 23 | |
Previous Owners [Member] | Link-Line and WS Nicholls [Member] | ||
Noncontrolling Interest [Line Items] | ||
Description of equity interest | In conjunction with the acquisition of the Canadian construction businesses in October 2014, the previous owners of the acquired companies retained a 3.4% equity interest in Centuri, which, subject to an eligibility timeline, would have been redeemable (in its entirety) at the election of the noncontrolling parties beginning in July 2022. In August 2017, in advance of when otherwise eligible, the parties agreed to a current redemption. Southwest Gas Holdings, Inc. paid $23 million to the previous owners, thereby acquiring the remaining 3.4% equity interest in Centuri. Accordingly, Centuri is now a wholly owned subsidiary of the Company. | |
Previous Owners [Member] | Link-Line and WS Nicholls [Member] | Construction Services [Member] | ||
Noncontrolling Interest [Line Items] | ||
Percentage of earnings attribution by Centuri to previous owners | 3.40% | |
IntelliChoice Energy Llc [Member] | ||
Noncontrolling Interest [Line Items] | ||
Subsidiaries holding interest percentage | 65.00% |
Construction Services Redeem122
Construction Services Redeemable Noncontrolling Interest - Summary of Redeemable Noncontrolling Interest (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Redeemable Noncontrolling Interest [Line Items] | |||
Beginning Balance | $ 22,590 | ||
Ending Balance | $ 22,590 | ||
Redeemable Noncontrolling Interest (Temporary Equity) [Member] | |||
Redeemable Noncontrolling Interest [Line Items] | |||
Beginning Balance | 22,590 | 16,108 | |
Net Income (loss) attributable to redeemable noncontrolling interest | 248 | 1,148 | $ 939 |
Foreign currency exchange translation adjustment | 11 | 5 | (66) |
Centuri distribution to redeemable noncontrolling interest | (204) | (439) | (99) |
Adjustment to redemption value | 355 | ||
Redemption of Centuri shares from noncontrolling parties | $ (23,000) | ||
Ending Balance | $ 22,590 | $ 16,108 |
Reorganization Impacts - Dis123
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation - Summary of Assets and Liabilities within Amounts Reported as Discontinued Operations - Construction Services in Condensed Consolidated Balance Sheet (Detail) - Construction Services [Member] - Southwest Gas Corporation [Member] $ in Thousands | Dec. 31, 2016USD ($) |
Assets: | |
Other property and investments | $ 233,774 |
Cash and cash equivalents | 9,042 |
Accounts receivable, net of allowances | 173,300 |
Prepaids and other current assets | 10,470 |
Goodwill | 129,888 |
Other noncurrent assets | 22,897 |
Discontinued operations - construction services - assets | 579,371 |
Liabilities: | |
Current maturities of long-term debt | 25,101 |
Accounts payable | 46,440 |
Other current liabilities | 74,518 |
Long-term debt, less current maturities | 174,903 |
Deferred income taxes and other deferred credits | 59,653 |
Discontinued operations - construction services - liabilities | $ 380,615 |
Reorganization Impacts - Dis124
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation - Components of Discontinued Operations - Construction Services Non-Owner Equity Amount in Condensed Consolidated Balance Sheet (Detail) - Southwest Gas Corporation [Member] $ in Thousands | Dec. 31, 2016USD ($) |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |
Discontinued operations - construction services non-owner equity | $ 15,983 |
Construction Services [Member] | |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |
Construction services equity | (4,390) |
Construction services noncontrolling interest | (2,217) |
Construction services redeemable noncontrolling interest | 22,590 |
Discontinued operations - construction services non-owner equity | $ 15,983 |
Reorganization Impacts - Dis125
Reorganization Impacts - Discontinued Operations Solely Related to Southwest Gas Corporation - Summary of Income Statement Components of Discontinued Operations - Construction Services in Condensed Consolidated Income Statements (Detail) - Southwest Gas Corporation [Member] - USD ($) $ in Thousands | 12 Months Ended | |
Dec. 31, 2016 | Dec. 31, 2015 | |
Operating expenses: | ||
Income before income taxes | $ 53,516 | $ 46,352 |
Income tax expense | 19,884 | 18,547 |
Net income | 33,632 | 27,805 |
Net income attributable to noncontrolling interests | 1,014 | 1,113 |
Discontinued operations - construction services - net income | 32,618 | 26,692 |
Construction Services [Member] | ||
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||
Construction revenues | 1,139,078 | 1,008,986 |
Operating expenses: | ||
Construction expenses | 1,024,423 | 898,781 |
Depreciation and amortization | 55,669 | 56,656 |
Operating income | 58,986 | 53,549 |
Other income (deductions) | 1,193 | 587 |
Net interest deductions | 6,663 | 7,784 |
Income before income taxes | 53,516 | 46,352 |
Income tax expense | 19,884 | 18,547 |
Net income | 33,632 | 27,805 |
Net income attributable to noncontrolling interests | 1,014 | 1,113 |
Discontinued operations - construction services - net income | $ 32,618 | $ 26,692 |
Acquisition of Construction 126
Acquisition of Construction Services Businesses - Additional Information (Detail) - USD ($) | 12 Months Ended | |||||
Dec. 31, 2017 | Nov. 30, 2017 | Nov. 29, 2017 | Nov. 01, 2017 | Oct. 31, 2017 | Dec. 31, 2016 | |
Business Acquisition [Line Items] | ||||||
Acquisition costs | $ 2,600,000 | |||||
New England Utility Constructors Inc [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Net consideration of acquisition less assumed debt | $ 99,000,000 | $ 99,300,000 | ||||
Intangible assets | 44,800,000 | $ 44,800,000 | ||||
Intangible assets, accumulated amortization | 700,000 | |||||
New England Utility Constructors Inc [Member] | Noncompete Agreement [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | 56,000 | |||||
Intangible assets | $ 1,000,000 | |||||
Intangible assets, useful life | 3 years | |||||
New England Utility Constructors Inc [Member] | Customer Relationships [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | $ 502,000 | |||||
Intangible assets | 40,000,000 | |||||
New England Utility Constructors Inc [Member] | Trade Names [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | 63,000 | |||||
Intangible assets | 3,800,000 | |||||
Goodwill expected tax deductible amount | $ 32,000,000 | |||||
New England Utility Constructors Inc [Member] | Minimum [Member] | Customer Relationships [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, useful life | 13 years | |||||
New England Utility Constructors Inc [Member] | Maximum [Member] | Customer Relationships [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, useful life | 14 years | |||||
Centuri Construction Group Inc [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | $ 11,366,000 | $ 8,398,000 | ||||
Centuri Construction Group Inc [Member] | Noncompete Agreement [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | 543,000 | 271,000 | ||||
Centuri Construction Group Inc [Member] | Customer Relationships [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Intangible assets, accumulated amortization | 6,743,000 | $ 3,906,000 | ||||
Centuri Construction Group Inc [Member] | Secured Revolving Credit and Term Loan Facility [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Credit facility maximum borrowing capacity | $ 450,000,000 | $ 450,000,000 | $ 300,000,000 | $ 300,000,000 |
Acquisition of Construction 127
Acquisition of Construction Services Businesses - Summary of Preliminary Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Nov. 30, 2017 | Nov. 01, 2017 | Dec. 31, 2016 |
Business Acquisition [Line Items] | ||||
Goodwill | $ 179,314 | $ 139,983 | ||
New England Utility Constructors Inc [Member] | ||||
Business Acquisition [Line Items] | ||||
Cash and cash equivalents | $ 800 | |||
Contracts receivable | 18,300 | |||
Other receivables | 5,400 | |||
Property, plant and equipment | 15,100 | |||
Prepaid expenses and deposits | 1,700 | |||
Intangible assets | $ 44,800 | 44,800 | ||
Goodwill | 32,000 | |||
Total assets acquired | 118,100 | |||
Current liabilities | (18,500) | |||
Other long-term liabilities | (300) | |||
Net assets acquired | $ 99,000 | $ 99,300 |
Acquisition of Construction 128
Acquisition of Construction Services Businesses - Summary of Estimated Future Amortization of Intangible Assets Acquired (Detail) $ in Thousands | Dec. 31, 2017USD ($) |
Finite-Lived Intangible Assets [Line Items] | |
2,018 | $ 6,835 |
2,019 | 6,240 |
2,020 | 6,114 |
2,021 | 5,711 |
2,022 | 5,626 |
New England Utility Constructors Inc [Member] | |
Finite-Lived Intangible Assets [Line Items] | |
2,018 | 3,641 |
2,019 | 3,724 |
2,020 | 3,669 |
2,021 | 3,391 |
2,022 | $ 3,391 |
Acquisition of Construction 129
Acquisition of Construction Services Business - Schedule of Pro Forma Consolidated Financial Information (Detail) - New England Utility Constructors Inc [Member] - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | |
Business Acquisition [Line Items] | ||
Total operating revenues | $ 2,639,452 | $ 2,556,124 |
Net income attributable to Southwest Gas Holdings, Inc. | $ 203,245 | $ 156,108 |
Basic earnings per share | $ 4.24 | $ 3.29 |
Diluted earnings per share | $ 4.24 | $ 3.26 |
Acquisition of Construction 130
Acquisition of Construction Services Business - Schedule of Statements of Income Operations (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | |||||||||||||
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | |
Condensed Income Statements, Captions [Line Items] | |||||||||||||||
Construction revenues | $ 1,246,484 | $ 1,139,078 | $ 1,008,986 | ||||||||||||
Net income attributable to Neuco | $ 96,465 | $ 10,204 | $ 17,864 | $ 69,308 | $ 65,180 | $ 2,472 | $ 8,943 | $ 75,446 | $ 66,119 | $ (4,734) | $ 4,949 | $ 71,983 | 193,841 | $ 152,041 | $ 138,317 |
New England Utility Constructors Inc [Member] | |||||||||||||||
Condensed Income Statements, Captions [Line Items] | |||||||||||||||
Construction revenues | 17,182 | ||||||||||||||
Net income attributable to Neuco | $ 2,772 |