PHI (PHIG) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	PHII
Entity Registrant Name	PHI INC
Entity Central Index Key	350,403
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Voting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,905,757
Non-Voting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		12,914,011

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash	$ 16,453	$ 8,770
Short-term investments	30,509	64,237
Accounts receivable – net
Trade	175,372	168,153
Other	22,035	17,826
Inventories of spare parts – net	74,352	80,881
Prepaid expenses	13,201	11,475
Income taxes receivable	649	1,271
Total current assets	332,571	352,613
Property and equipment – net	923,577	946,765
Restricted investments	19,781	12,396
Other assets	10,142	8,741
Deferred income taxes	1,009	3,309
Goodwill	61,299	61,299
Intangibles	15,557	16,723
Total assets	1,363,936	1,401,846
Current Liabilities:
Senior Notes issued March 17, 2014, net of debt issuance costs of $571	499,429	0
Accounts payable	39,209	37,186
Accrued and other current liabilities	39,557	41,850
Total current liabilities	578,195	79,036
Long-term debt:
Revolving credit facility	0	117,500
Senior Notes issued March 17, 2014, net of debt issuance costs of $1,506	0	498,494
Related Party Term Loan issued September 28, 2018, net of debt issuance costs of $874	129,126	0
Deferred income taxes	74,062	86,005
Other long-term liabilities	5,168	8,157
Commitments and contingencies (Note 9)
Shareholders’ Equity:
Additional paid-in capital	312,503	308,353
Accumulated other comprehensive income (loss)	(4,094)	(280)
Retained earnings	267,394	303,001
Total shareholders’ equity	577,385	612,654
Total liabilities and shareholders’ equity	1,363,936	1,401,846
Voting Common Stock [Member]
Shareholders’ Equity:
Common stock	291	291
Non-Voting Common Stock [Member]
Shareholders’ Equity:
Common stock	1,291	1,289
Total shareholders’ equity	$ 1,291	$ 1,289

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Voting Common Stock [Member]
Common stock, par value (in USD per share)	$ 0.10	$ 0.10
Common stock, shares authorized (shares)	12,500,000	12,500,000
Common stock, shares issued (shares)	2,905,757	2,905,757
Common stock, shares outstanding (shares)	2,905,757	2,905,757
Non-Voting Common Stock [Member]
Common stock, par value (in USD per share)	$ 0.10	$ 0.10
Common stock, shares authorized (shares)	37,500,000	37,500,000
Common stock, shares issued (shares)	12,914,011	12,897,614
Common stock, shares outstanding (shares)	12,914,011	12,897,614
Senior Notes [Member]
Debt issuance costs	$ 571	$ 1,506
Note Payable, Related Party [Member]
Debt issuance costs	$ 874	$ 0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Operating revenues, net	$ 168,787	$ 150,167	$ 498,400	$ 431,209
Expenses:
Direct expenses	160,200	136,786	471,509	400,250
Selling, general and administrative expenses	16,255	11,401	46,199	38,691
Total operating expenses	176,455	148,187	517,708	438,941
(Gain) loss on disposal of assets	0	(4)	708	3
Equity in (gain) loss of unconsolidated affiliates, net	(118)	(438)	(162)	1,556
Operating (loss) income	(7,550)	2,422	(19,854)	(9,291)
Interest expense	8,357	8,027	24,894	24,305
Other income – net	(1,845)	(706)	(436)	(2,474)
Total expenses	6,512	7,321	24,458	21,831
Loss before income taxes	(14,062)	(4,899)	(44,312)	(31,122)
Income tax benefit	(2,531)	(1,622)	(8,705)	(9,324)
Net loss	$ (11,531)	$ (3,277)	$ (35,607)	$ (21,798)
Weighted average shares outstanding:
Basic (shares)	15,816	15,799	15,811	15,750
Diluted (shares)	15,816	15,799	15,811	15,750
Net loss per share:
Basic (in USD per share)	$ (0.73)	$ (0.21)	$ (2.25)	$ (1.38)
Diluted (in USD per share)	$ (0.73)	$ (0.21)	$ (2.25)	$ (1.38)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (11,531)	$ (3,277)	$ (35,607)	$ (21,798)
Unrealized gain on short-term investments	0	41	363	370
Currency translation adjustments	(4,718)	0	(4,091)	0
Changes in pension plan assets and benefit obligations	0	(24)	(1)	(2)
Tax effect of the above-listed adjustments	0	(8)	(85)	(134)
Total comprehensive loss	$ (16,249)	$ (3,268)	$ (39,421)	$ (21,564)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Non-Voting Common Stock [Member]	Voting Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2016	$ 599,778	$ 1,278	$ 291	$ 304,246	$ (478)	$ 294,441
Balance, Shares at Dec. 31, 2016		12,779	2,906
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(21,798)					(21,798)
Unrealized gain on short-term investments	235				235
Changes in pension plan assets and benefit obligations	(1)				(1)
Amortization of unearned stock-based compensation	3,074			3,074
Issuance of non-voting common stock (upon vesting of restricted stock units)	3	$ 13		(10)
Issuance of non-voting common stock (upon vesting of restricted stock units), shares		136
Cancellation of restricted non-voting stock units for tax withholdings on vested shares	(258)	$ (2)		(256)
Cancellation of restricted non-voting stock units for tax withholdings on vested shares, Shares		(22)
Retirement of treasury stock	1,028					1,028
Balance at Sep. 30, 2017	582,061	$ 1,289	$ 291	307,054	(244)	273,671
Balance, Shares at Sep. 30, 2017		12,893	2,906
Balance at Dec. 31, 2017	612,654	$ 1,289	$ 291	308,353	(280)	303,001
Balance, Shares at Dec. 31, 2017		12,897	2,906
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(35,607)					(35,607)
Unrealized gain on short-term investments	278				278
Changes in pension plan assets and benefit obligations	(1)				(1)
Amortization of unearned stock-based compensation	4,250			4,250
Currency translation adjustment	(4,091)				(4,091)
Issuance of non-voting common stock (upon vesting of restricted stock units)	3	$ 3		0
Issuance of non-voting common stock (upon vesting of restricted stock units), shares		27
Cancellation of restricted non-voting stock units for tax withholdings on vested shares	(101)	$ (1)		(100)
Cancellation of restricted non-voting stock units for tax withholdings on vested shares, Shares		(10)
Balance at Sep. 30, 2018	$ 577,385	$ 1,291	$ 291	$ 312,503	$ (4,094)	$ 267,394
Balance, Shares at Sep. 30, 2018		12,914	2,906

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (35,607)	$ (21,798)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	59,541	50,593
Deferred income taxes	(9,734)	(9,416)
Loss (gain) on asset dispositions	708	3
Equity in loss of unconsolidated affiliate, net	(162)	1,556
Inventory valuation reserves	1,234	(3)
Changes in operating assets and liabilities	(24,028)	(22,803)
Net cash used in operating activities	(8,048)	(1,868)
Investing activities:
Purchase of property and equipment	(22,761)	(49,227)
Proceeds from asset dispositions	1,453	21
Purchase of short-term investments	(284,277)	(268,525)
Purchase of restricted investments	(7,705)	0
Proceeds from sale of short-term investments	318,007	354,250
Loan to unconsolidated affiliate	(274)	0
Net cash provided by investing activities	4,443	36,519
Financing activities:
Debt issuance cost	(874)	0
Proceeds from line of credit	34,295	99,150
Payments on line of credit	(151,795)	(133,150)
Proceeds from Term Loan	(130,000)	0
Repurchase of common stock	(99)	(256)
Net cash provided by (used in) financing activities	11,527	(34,256)
Effect of exchange rate changes on cash	(239)	0
Increase in cash	7,683	395
Cash, beginning of period	8,770	2,596
Cash, end of period	16,453	2,991
Cash paid during the period for:
Interest	30,825	29,536
Income taxes	1,304	1,213
Noncash investing activities:
Other current liabilities and accrued payables related to purchase of property and equipment	$ 223	$ 21

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements include the accounts of PHI, Inc. and its subsidiaries (“PHI” or the “Company” or “we” or “our”). In the opinion of management, these condensed consolidated financial statements reflect all adjustments, consisting of only normal, recurring adjustments, necessary to present fairly the financial results for the interim periods presented. These condensed consolidated financial statements and the accompanying notes should be read in conjunction with the consolidated financial statements and the accompanying notes contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Our financial results, particularly as they relate to our Oil and Gas segment, are influenced by seasonal fluctuations as discussed in our Annual Report on Form 10-K for the year ended December 31, 2017 . For this and other reasons, the results of operations for interim periods are not necessarily indicative of the operating results that may be expected for a full fiscal year. Going Concern - The financial statements accompanying this Quarterly Report have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”), which contemplates our continuation as a going concern. For the reasons described in Note 5, the classification of our senior note indebtedness as current liabilities due within one year and other conditions raise substantial doubt about our ability to continue as a going concern within one year after the date the financial statements accompanying this Quarterly Report are filed. Recently Adopted Accounting Pronouncements - In 2014, the Financial Accounting Standard Board ("the FASB") issued ASC 606, Revenue from Contracts with Customers (“ASC 606”), replacing the existing accounting standard and industry specific guidance for revenue recognition with a five-step model for recognizing and measuring revenue from contracts with customers. The underlying principle of the new standard is to recognize revenue to depict the transfer of goods or services to customers at the amount expected to be collected. ASC 606 became effective on January 1, 2018 and we adopted it using the modified retrospective method applied to open contracts and only to the version of the contracts in effect as of January 1, 2018. Prior period amounts have not been adjusted and continue to be reflected in accordance with our historical accounting. There was no impact on the condensed consolidated financial statements and no cumulative effect adjustment was recognized. In general, under ASC 606, we recognize revenue when a service or good is sold to a customer and there is a contract. At contract inception, we assess the goods and services promised in our contracts with customers and identify all performance obligations for each distinct promise that transfers a good or service (or bundle of goods or services) to the customer. To identify the performance obligations, we consider all goods or services promised in the contract, whether explicitly stated or implied based on customary business practices. Revenue is recognized when control of the identified distinct goods or services has been transferred to the customer, the transaction price has been determined and allocated to the performed performance obligations and we have determined that collection has occurred or is probable of occurring. We measure revenue as the amount of consideration we expect to receive in exchange for the services provided. Taxes collected from customers and remitted to governmental authorities and revenues are reported on a net basis in the our financial statements. Thus, we exclude taxes imposed on the customer and collected on behalf of governmental agencies to be remitted to these agencies from the transaction price in determining the revenue related to contracts with a customer. Oil & Gas Revenue Recognition - We provide helicopter services to oil and gas customers operating in the Gulf of Mexico and a number of foreign countries. Revenues are recognized when performance obligations are satisfied over time in accordance with contractual terms, in an amount that reflects the consideration the Company expects to be entitled to in exchange for services rendered. Air Medical Revenue Recognition - We provide helicopter services to hospitals and emergency service providers in several U.S. states, or to individual patients in the U.S. in which case we are paid by either a commercial insurance company, federal or state agency, or the patient. Our Air Medical segment operates primarily under the independent provider model and, to a lesser extent, under the traditional provider model. Revenues related to the independent provider model services are recorded in the period in which we satisfy our performance obligations under contracts by providing our services to our customers based upon established billing rates net of contractual allowances under agreements with third party payors and net of uncompensated care allowances. These amounts are due from patients, third-party payors (including health insurers and government programs), and others and includes variable consideration for retroactive revenue adjustments due to settlement of audits, reviews, and investigations. Generally, we bill the patients and third-party payors several days after the services are performed. Revenues generated under the traditional provider model are recognized as performance obligations are satisfied over time in accordance with contractual terms, in an amount that reflects the consideration the Company expects to be entitled in exchange for services rendered. Oil & Gas Performance Obligations - A performance obligation arises under contracts with customers to render services and is the unit of account under ASC 606. Operating revenue from our Oil and Gas segment is derived mainly from fixed-term contracts with our customers, a substantial portion of which are competitively bid. A small portion of our Oil and Gas segment revenue is derived from providing services on an "ad-hoc" basis. Our fixed-term contracts typically have original terms of one to seven years (subject to provisions permitting early termination on relatively short notice by the customers), with payment in U.S. dollars. We account for services rendered separately if they are distinct and the services are separately identifiable from other items provided to a customer and if a customer can benefit from the services rendered on its own or with other resources that are readily available to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Within this contract type for helicopter services, we determined that each contract has a single distinct performance obligation. These services include a fixed monthly rate for a particular model of aircraft, and flight hour services, which represents the variable component of a typical contract with a customer. Rates for these services vary depending on the type of services provided and can be based on a per flight hour, per day, or per month basis. We also provide services to clients on an “ad hoc” basis, which usually entails a shorter contract notice period and duration. The charges for ad hoc services are based on an hourly rate or a daily or monthly fixed fee plus additional fees for each hour flown. The nature of our variable charges within our flight services contracts are not effective until a customer-initiated flight order and the actual hours flown are determined; therefore, the associated flight revenue generally cannot be reasonably and reliably estimated before hand. A contract’s standalone selling prices are determined based upon the prices that we charge for our services rendered. The majority of our revenue is recognized as performance obligations satisfied over time, by measuring progress towards satisfying the contracted services in a manner that best depicts the transfer of services to the customer, which is generally represented by a period of 30 days or less. We typically invoice customers on a monthly basis with the term between invoicing and when the payment is due typically being between 30 and 60 days. Air Medical Performance Obligations - Performance obligations are determined based upon the nature of the services provided. Under the independent provider model, we measure the performance obligation from the moment the patient is loaded into the aircraft until it reaches its destination. Under this model, we have no fixed revenue stream and compete for transport referrals on a daily basis with other independent operators in the area. As an independent provider, we bill for our services on the basis of a flat rate plus a variable charge per patient-loaded mile, regardless of aircraft model, and are typically compensated by private insurance, Medicaid or Medicare, or directly by transported patients who self-pay. We recognize revenues for performance obligations satisfied at a point in time, which generally relate to patients receiving air medical services when: (1) services are provided; and (2) we do not believe the patient requires additional services. For the independent provider model, we determine the transaction price based upon gross charges for services provided reduced by contractual adjustments provided to third-party payors, discounts provided to uninsured patients in accordance with Company policy, and/or implicit price concessions provided to uninsured patients. We determine estimates of contractual adjustments and discounts based upon contractual agreements, our discount policy, and historical experience. We determine our estimate of implicit price concessions based upon our historical collection experience with these classes of patients using a portfolio approach as a practical expedient to account for patient contracts as collective groups, rather than individually. The financial statement effects of using this practical expedient are not materially different from an individual contract approach. Under the traditional provider model, we contract directly with the customer to provide their transportation services. These contracts are typically awarded or renewed through competitive bidding and typically permit early termination by the customer on relatively short notice. As a traditional provider, we typically bill a fixed monthly rate for aircraft availability and an hourly rate for flight time. For each of these types of helicopter services, we have determined that each has a single distinct performance obligation. Traditional provider models services include fixed monthly rate for a particular model of aircraft, and flight hour services, which represents the variable component of a typical contract with a customer. Rates for these services vary depending on the type of services provided and can be based on a per flight hour, per day, or per month basis. The variable charges within such contracts are not effective until the customer initiates a flight order and the actual hours flown are determined; therefore, the associated revenue generally cannot be reasonably and reliably estimated beforehand. For the traditional provider model, we determine the transaction price based upon standard charges for goods and services provided. As further described in Note 3, independent provider revenues are recorded net of contractual allowances under agreements with third party payors and estimated uncompensated care at the time the services are provided. Contractual allowances and uncompensated care are estimated based on historical collection experience by payor category (consisting mainly of private insurance, Medicaid, Medicare, and self-pay). The allowance percentages calculated are applied to the payor categories, and the necessary adjustments are made to the revenue allowance. Agreements with third-party payors typically provide for payments at amounts less than established charges. As of September 30, 3018 and December 31, 2017, receivables related to our (i) Oil and Gas segment were $103.1 million and $106.8 million , (ii) Air Medical segment were $91.8 million and $74.4 million and (iii) Technical Services segment were $2.5 million and $4.8 million , respectively. Contract assets and contract liabilities were immaterial as of September 30, 2018. Our contracts typically include termination clauses that allow both parties to terminate existing contracts with a 30 to 180 day notice period. We generally have a right to consideration in an amount that corresponds directly with the value to the customer of the entity's performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. We have elected to use the invoice practical expedient for revenue recognized when performance obligations are satisfied over time. In addition, payment for goods and services rendered is typically due in the subsequent month following satisfaction of our performance obligation. Our Technical Services segment provides helicopter flight services and helicopter repair and overhaul services for existing flight operations customers that own their own aircraft. Under this segment, we periodically provide certain services to governmental customers, including our agreement to operate six aircraft for the National Science Foundation in Antarctica. Under this segment, we also offer certain software as a service to our Oil and Gas customers. Revenues are recognized when performance obligations are satisfied in accordance with contractual terms, in an amount that reflects the consideration we expect to be entitled to in exchange for services rendered. For these helicopter services, we determined that each has a single distinct performance obligation. The following table presents the Company’s revenues by segment disaggregated by type (in thousands): For the Quarter Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Service Revenue Oil & Gas $ 93,338 $ 75,700 $ 286,046 $ 222,098 Air Medical 70,192 70,280 194,331 192,840 Technical Services 5,257 4,187 18,023 16,271 Total Services $ 168,787 $ 150,167 $ 498,400 $ 431,209 Air Medical Revenue Traditional provider model $ 12,414 $ 11,816 $ 36,371 $ 35,427 Independent provider model 57,778 58,464 157,960 157,413 Total Air Medicals Revenues $ 70,192 $ 70,280 $ 194,331 $ 192,840 On January 26, 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) : Simplifying the Test for Goodwill Impairment (ASU 2017-04). ASU 2017-04 removes the requirement to compare the implied fair value of goodwill with the carrying amount as part of Step 2 of the goodwill impairment test. Under the new standard, the goodwill impairment loss will be measured as the excess of a reporting unit's carrying amount over its fair value, not exceeding the total amount of goodwill allocated to that reporting unit, which may increase the frequency of goodwill impairment charges if a future goodwill impairment test does not pass the Step 1 evaluation. ASU 2017-04 is effective prospectively for periods beginning on or after December 15, 2019, with early adoption permitted. We adopted ASU 2017-04 effective January 1, 2018. We will perform goodwill impairment testing under the new standard annually as of October 1st or when events or changes in circumstances indicate that a potential impairment exist. In November 2015, the FASB issued ASU 2015-17, Balance Sheet Classification of Deferred Taxes , which requires that deferred tax assets and liabilities be classified as noncurrent in a classified balance sheet. We adopted this ASU in the fourth quarter of 2017 on a prospective basis. Beginning with the December 31, 2017 balances, all deferred taxes were classified as non-current. Periods prior to December 31, 2017 were not retrospectively adjusted. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other than Inventory , which will require an entity to recognize the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. We adopted ASU 2016-16 effective January 1, 2018 with no material impact to the condensed consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business . ASU 2017-01 clarifies the definition of a business and requires that an entity apply certain criteria in order to determine when a set of assets and activities qualifies as a business. The adoption of this standard is expected to result in fewer acquisitions of properties qualifying as acquisitions of businesses and, accordingly, acquisition costs for those acquisitions that do not qualify as businesses will be capitalized rather than expensed. This standard is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, and should be applied on a prospective basis. We adopted ASU 2017-01 effective January 1, 2018 with no material impact to the condensed consolidated financial statements. On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted which significantly reformed the U.S. Internal Revenue Code (the “Code”). The Tax Act, among other things, reduced the federal corporate income tax rate from 35% to 21% effective January 1, 2018. Following the enactment of the Tax Act, the SEC staff issued Staff Accounting Bulletin 118 - "Income Tax Accounting Implications of the Tax Cuts and Jobs Act" (SAB 118), which provides for a measurement period of up to one year from the enactment date to complete accounting under GAAP for the tax effects of the legislation. As of December 31, 2017, we had not completed its accounting for the tax effects of the Tax Act, but did remeasure its net deferred tax liability at December 31, 2017 and provisionally recognized a net benefit of $49.2 million in its consolidated statement of operations for the year ended December 31, 2017. As of September 30, 2018, we had not completed its accounting for the tax effects of the Tax Act and had not recorded any adjustments to the original provisional estimate. Although it does not anticipate any material adjustments related to the Tax Act, we will continue analyzing certain aspects of the Tax Act and refining its calculations, which could potentially affect the measurement of these balances or potentially give rise to changes to its current provisional estimates. Our estimates may be affected by a wide variety of factors, including additional regulatory guidance issued with respect to the Tax Act. In accordance with SAB 118, any subsequent adjustments to our provisional estimate will be recorded in the 4th quarter of 2018. New Accounting Pronouncements - In February 2016, the FASB issued ASU 2016-02, Leases , which replaces the existing guidance on leasing transactions in ASC 840 to require recognition of the assets and liabilities for the rights and obligations created by those leases on the balance sheet. We have formed an implementation team that is inventorying leases under ASC 840 and contracts which may be leases under ASC 842, and evaluating the impact that adoption of this guidance will have on the Company’s financial statements, which includes monitoring industry specific developments including recent exposure drafts issued by the FASB. The Company is continuing work to complete the implementation of an information technology system to track and account for its leases and of changes to its internal controls and accounting policies to support the accounting for leases under ASU 2016-02. Based on our lease portfolio as of September 30, 2018, we expect the adoption of this standard will result in a material change to our consolidated assets and liabilities. We plan to adopt this standard beginning January 1, 2019.

Investments

Investments	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	INVESTMENTS We classify all of our short-term investments as available-for-sale. We carry these at fair value and report unrealized gains and losses, net of taxes, in Accumulated other comprehensive loss, which is a separate component of shareholders’ equity in our Condensed Consolidated Balance Sheets. These unrealized gains and losses are also reflected in our Condensed Consolidated Statements of Comprehensive Income and Condensed Consolidated Statements of Shareholders’ Equity. We determine cost, gains, and losses using the specific identification method. Investments consisted of the following as of September 30, 2018 : Cost Basis Unrealized Unrealized Fair (Thousands of dollars) Investments: Money market mutual funds $ 50,290 $ — $ — $ 50,290 Deferred compensation plan assets included in other assets 852 — — 852 Total $ 51,142 $ — $ — $ 51,142 Investments consisted of the following as of December 31, 2017 : Cost Basis Unrealized Gains Unrealized Losses Fair Value (Thousands of dollars) Investments: Money market mutual funds $ 5,601 $ — $ — $ 5,601 U.S. government agencies 7,501 — (34 ) 7,467 Corporate bonds and notes 63,880 — (330 ) 63,550 Subtotal 76,982 — (364 ) 76,618 Deferred compensation plan assets included in other assets 2,685 — — 2,685 Total $ 79,667 $ — $ (364 ) $ 79,303 At September 30, 2018 and December 31, 2017 , we classified $19.8 million and $12.4 million , respectively of our aggregate investments as long-term investments and recorded them in our Condensed Consolidated Balance Sheets as restricted cash and investments, as they are securing outstanding letters of credit with maturities beyond one year. The following table presents the cost and fair value of our debt investments based on maturities as of: September 30, 2018 December 31, 2017 Amortized Fair Amortized Fair (Thousands of dollars) Due in one year or less $ — $ — $ 31,348 $ 31,254 Due within two years — — 40,032 39,763 Total $ — $ — $ 71,380 $ 71,017 The following table presents the average coupon rate percentage and the average days to maturity of our debt investments as of: September 30, 2018 December 31, 2017 Average Average Average Average U.S. Government agencies — 0 1.370 370 Corporate bonds and notes — 0 1.766 392 The following table presents the fair value and unrealized losses related to our investments that have been in a continuous unrealized loss position for less than twelve months as of: September 30, 2018 December 31, 2017 Fair Value Unrealized Fair Value Unrealized (Thousands of dollars) U.S. Government agencies $ — $ — $ 5,472 $ (28 ) Corporate bonds and notes — — 44,069 (271 ) Total $ — $ — $ 49,541 $ (299 ) The following table presents the fair value and unrealized losses related to our investments that have been in a continuous unrealized loss position for more than twelve months as of: September 30, 2018 December 31, 2017 Fair Value Unrealized Fair Value Unrealized (Thousands of dollars) U.S. Government agencies $ — $ — $ 1,994 $ (6 ) Corporate bonds and notes — — 19,482 (59 ) Total $ — $ — $ 21,476 $ (65 ) From time to time over the periods covered in our financial statements included herein (and as illustrated in the foregoing tables), our investments have experienced net unrealized losses. We consider these declines in market value to be due to customary market fluctuations, and we typically do not plan to sell these investments prior to maturity. For these reasons, we do not consider any of our investments to be other than temporarily impaired at December 31, 2017 . For additional information regarding our criteria for making these assessments, see Note 2 to the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017 .

Valuation Accounts

Valuation Accounts	9 Months Ended
	Sep. 30, 2018
Revenue Recognition And Valuation Accounts [Abstract]
Revenue Recognition and Valuation Accounts	VALUATION ACCOUNTS We establish the amount of our allowance for doubtful accounts based upon factors relating to the credit risk of specific customers, current market conditions, and other information. Our allowance for doubtful accounts was approximately $6.8 million and $7.2 million at September 30, 2018 , and December 31, 2017 , respectively. Revenues related to flights generated by our Air Medical segment are recorded net of contractual allowances under agreements with third party payors and estimated uncompensated care when the services are provided. The allowance for contractual discounts was $119.9 million and $117.8 million as of September 30, 2018 and December 31, 2017 , respectively. The allowance for uncompensated care was $64.7 million and $52.5 million as of September 30, 2018 and December 31, 2017 , respectively. Included in the allowance for uncompensated care listed above is the value of services to patients who are unable to pay when it is determined that they qualify for charity care. The value of these services was $2.2 million and $1.3 million for the quarters ended September 30, 2018 and 2017 , respectively. The value of these services was $7.1 million and $5.7 million for the nine months ended September 30, 2018 and 2017 , respectively. The estimated cost of providing charity services was $0.5 million and $0.3 million for the quarters ended September 30, 2018 and 2017, respectively. The estimated cost of providing charity services was $1.7 million and $1.3 million for the nine months ended September 30, 2018 and 2017 , respectively. The estimated costs of providing charity services are based on a calculation that applies a ratio of costs to the charges for uncompensated charity care. The ratio of costs to charges is based on our Air Medical segment’s total expenses divided by gross patient service revenue. The allowance for contractual discounts and estimated uncompensated care (expressed as a percentage of gross segment accounts receivable) as of the dates listed below was as follows: September 30, 2018 December 31, 2017 Allowance for Contractual Discounts 48% 53% Allowance for Uncompensated Care 26% 24% We have also established valuation reserves related to obsolete and slow-moving spare parts inventory. The inventory valuation reserves were $23.1 million and $20.9 million at September 30, 2018 and December 31, 2017 , respectively.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Accounting standards require that assets and liabilities carried at fair value will be classified and disclosed in one of the following three categories: Level 1: Quoted market prices in active markets for identical assets or liabilities. Level 2: Observable market based inputs or unobservable inputs that are corroborated by market data. Level 3: Unobservable inputs that are not corroborated by market data. The following table summarizes the valuation of our investments and financial instruments by the above pricing levels as of the valuation dates listed: September 30, 2018 Total (Level 1) (Level 2) (Thousands of dollars) Investments: Money market mutual funds $ 50,290 $ 50,290 $ — Deferred compensation plan assets 852 852 — Total $ 51,142 $ 51,142 $ — December 31, 2017 Total (Level 1) (Level 2) (Thousands of dollars) Investments: Money market mutual funds $ 5,601 $ 5,601 $ — U.S. government agencies 7,467 — 7,467 Corporate bonds and notes 63,550 — 63,550 76,618 5,601 71,017 Deferred compensation plan assets 2,685 2,685 — Total $ 79,303 $ 8,286 $ 71,017 We hold our short-term investments in an investment fund consisting of high quality money market instruments of governmental and private issuers, which is classified as a short-term investment. Level 1 inputs are quoted prices (unadjusted) for identical assets or liabilities in active markets. These items are traded with sufficient frequency and volume to provide pricing on an ongoing basis. The fair values of the investments in these funds are based on observable market prices, and therefore, have been categorized in Level 1 in the fair value hierarchy. Level 2 inputs reflect quoted prices for identical assets or liabilities that are not actively traded. These items may not be traded daily; examples include commercial paper, corporate bonds and U.S. government agencies debt. There have been no reclassifications of assets between Level 1 and Level 2 investments during the periods covered by the financial statements included in this report. We hold no Level 3 investments. Investments reflected on our balance sheets as Other Assets, which we hold to fund liabilities under our Officers’ Deferred Compensation Plan, consist mainly of multiple investment funds that are highly liquid and diversified. Cash, accounts receivable, accounts payable and accrued liabilities, and term loan / revolving credit facility debt all had fair values approximating their carrying amounts at September 30, 2018 and December 31, 2017 . We determine the estimated fair value of our 5.25% Senior Notes due 2019 using Level 2 inputs, including quoted market indications of similar publicly-traded debt. The fair value of our 5.25% Senior Notes due 2019, based on quoted market prices, was $477.1 million and $499.2 million at September 30, 2018 and December 31, 2017 , respectively.

Debt

Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Debt	DEBT Listed below is information regarding our indebtedness. All indebtedness owed under our Senior Notes as of September 30, 2018 is classified as short-term debt on our balance sheet as of such date. September 30, 2018 December 31, 2017 Principal Unamortized Principal Unamortized (Thousands of dollars) Senior Notes issued March 17, 2014, interest only payable semi-annually at 5.25%, maturing March 15, 2019 $ 500,000 $ 571 $ 500,000 $ 1,506 Revolving Credit Facility due March 7, 2019 with a group of commercial banks, interest payable at variable rates — — 117,500 — Related Party Term Loan - Thirty Two L.L.C., interest payable quarterly at 6%, due September 28, 2020 $ 130,000 $ 874 $ — $ — Total indebtedness $ 630,000 $ 1,445 $ 617,500 $ 1,506 Senior Notes - Our 5.25% Senior Notes (the “2019 Notes”) will mature on March 15, 2019 , are unconditionally guaranteed on a senior basis by each of PHI, Inc.’s wholly-owned domestic subsidiaries. These notes and related guarantees are the general, unsecured obligations of PHI, Inc. and the guarantors. Interest is payable semi-annually on March 15 and September 15 of each year. PHI has the option to redeem some or all of the 2019 Notes at any time on or after March 15, 2018 at par plus accrued interest. The indenture governing the 2019 Notes (the “2019 Indenture”) contains, among other things, certain restrictive covenants, including limitations on incurring indebtedness, creating liens, selling assets and entering into certain transactions with affiliates. The covenants also limit PHI’s ability to, among other things, pay cash dividends on common stock, repurchase or redeem common or preferred equity, prepay subordinated debt and make certain investments. Upon the occurrence of a “Change in Control Repurchase Event” (as defined in the 2019 Indenture), PHI will be required, unless it has previously elected to redeem the 2019 Notes as described above, to make an offer to purchase the 2019 Notes for a cash price equal to 101% of their principal amount. Related Party Term Loan - On September 28, 2018, we entered into a term loan agreement with Thirty Two L.L.C., which provided us with a term loan of $130 million maturing on September 28, 2020. This loan bears interest at an annual fixed rate of 6% payable quarterly, with all principal due on maturity. Thirty Two L.L.C., an entity wholly-owned by our CEO and controlling shareholder, is a related party. Contemporaneously with borrowing $130.0 million under the term loan, we applied approximately $122.7 million of the loan proceeds to repay principal and accrued interest under our senior secured revolving credit facility, which was terminated in connection with such repayment, and applied the remainder of the proceeds to cash collateralize certain outstanding letters of credit. Obligations under the term loan are guaranteed by PHI Air Medical, L.L.C. and PHI Tech Services, Inc., both of which are wholly-owned by us. Our obligations and the guarantors’ obligations are secured by all of their respective inventory, spare parts and accounts receivable located in the U.S. The term loan agreement contains customary restrictive covenants that, subject to certain exceptions and limitations, limit or restrict our ability to, among other things, (i) purchase, retire or redeem any shares of our capital stock; (ii) incur indebtedness; (iii) mortgage or encumber our assets; (iv) make loans to, or guarantee the indebtedness of, any individual or entity; (v) effect a change of control of PHI; (vi) consolidate with or merge into any other corporation, or permit any other corporation to merge into us; (vii) sell or lease all or substantially all of our assets; or (viii) acquire all or a substantial part of the assets or capital stock of another entity. The term loan agreement contains no financial covenants. The term loan agreement contains customary representations and warranties, affirmative covenants and events of default. Letter of Credit - At September 30, 2018, we had $19.8 million of outstanding letters of credit secured by a like amount of restricted cash, $12.0 million of which secured certain domestic operations or insurance policies and $7.8 million of which guaranteed our performance under an international contract. At December 31, 2017, we had $19.6 million of outstanding letters of credit issued for the same purposes. Other - PHI, Inc. has cash management arrangements with certain of its principal subsidiaries, in which substantial portions of the subsidiaries’ cash is regularly advanced to PHI, Inc. Although PHI, Inc. periodically repays these advances to fund the subsidiaries’ cash requirements throughout the year, at any given point in time PHI, Inc. may owe a substantial sum to its subsidiaries under these advances, which, in accordance with GAAP, are eliminated in consolidation and therefore not recognized on our consolidated balance sheets. For additional information, see Note 15. Liquidity - Our outstanding senior notes mature on March 15, 2019. As such, our senior note indebtedness is now due within less than one year. Beginning with our consolidated financial statements as of and for the quarter ended March 31, 2018, we have been required to classify under GAAP all such indebtedness as current liabilities on our consolidated balance sheets. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern” (the "Standard"). Under the Standard, management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about an entity’s ability to continue as a going concern within one year after the date that the entity’s financial statements are issued. Under the Standard, substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within this one year period. This evaluation initially must be undertaken without considering the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this initial determination, management must evaluate whether the mitigating effect of its plans sufficiently alleviates substantial doubt about an entity’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered under the Standard if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within the one year period. Generally, to be considered probable of being effectively implemented, the plans must have been approved before the date that the financial statements are issued. PHI’s accompanying financial statements have been prepared in conformity with GAAP, which contemplates PHI’s continuation as a going concern. Based on our discussions to date with our advisors and current market conditions, we believe there are several possible transactions that could, if timely and successfully consummated, help us discharge our short-term indebtedness. Nonetheless, because our plans have not been finalized, and therefore not within our control, these plans cannot be considered probable. Consequently, in accordance with the Standard, these conditions in the aggregate raise substantial doubt about our ability to continue as a going concern within one year after the date the accompanying financial statements were filed. For additional information about our prior and current refinancing plans, see “Management’s Discussion and Analysis of Financial Condition and Results of Operations - Liquidity and Capital Resources.”

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The components of basic and diluted earnings per share for the quarter and nine months ended September 30, 2018 and 2017 are as follows: Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Weighted average outstanding shares of common stock, basic 15,816 15,799 15,811 15,750 Dilutive effect of unvested restricted stock units — — — — Weighted average outstanding shares of common stock, diluted (1) 15,816 15,799 15,811 15,750 (1) For the quarters ended September 30, 2018 and 2017, 108,424 and - 0 - unvested restricted stock units were excluded from the weighted average outstanding shares of common stock, diluted, respectively, as they were anti-dilutive to earnings per share. For the nine months ended on both September 30, 2018 and 2017 , - 0 - unvested restricted stock units were excluded from the weighted average outstanding shares of common stock, diluted, as they were anti-dilutive to earnings per share.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION We recognize the cost of employee compensation received in the form of equity instruments based on the grant date fair value of those awards. The table below sets forth the total amount of stock-based compensation expense for the quarter and nine months ended September 30, 2018 and 2017 . Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Stock-based compensation expense: Time-based restricted stock units $ 1,085 $ 582 $ 2,162 $ 1,678 Performance-based restricted stock units 1,033 689 2,088 1,396 Total stock-based compensation expense $ 2,118 $ 1,271 $ 4,250 $ 3,074 During the quarter and nine months ended September 30, 2018, 5,001 and 326,832 time-based restricted units, respectively and - 0 - and 448,012 performance-based restricted units, respectively, were awarded to managerial employees. During the quarter and nine months ended September 30, 2017, 26,296 and 472,913 time-based restricted units, respectively and 4,646 and 371,045 performance-based restricted units were awarded to managerial employees, respectively.

Asset Disposals

Asset Disposals	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Asset Disposals	ASSET DISPOSALS During the first quarter of 2018, we disposed of one light aircraft previously utilized in the Air Medical segment and donated to a charitable organization one aircraft previously used in our Oil and Gas segment. During the second quarter of 2018, we disposed of one medium and one light aircraft previously utilized in the Oil & Gas segment. During the third quarter of 2018, we disposed of one medium aircraft previously utilized in the Oil & Gas segment. These aircraft no longer met our strategic needs. Aggregate cash proceeds totaled $1.5 million , resulting in a $0.7 million loss on the disposal of these assets. There were no sales or disposals of aircraft during the first quarter of 2017. During the second quarter of 2017, we disposed of five medium aircraft. During the third quarter of 2017, we disposed of one medium aircraft and related parts inventory utilized in the Oil and Gas segment. These aircraft no longer met our strategic needs.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Commitments – We currently have no aircraft purchase commitments. Total aircraft deposits of $0.5 million were included in Other Assets as of September 30, 2018 . This amount represents a deposit on a future lease buyout option. In the event we do not exercise the buyout option, the deposit will be applied against lease payments. Environmental Matters – We have recorded an estimated liability of $0.15 million as of September 30, 2018 for environmental response costs. Previously, we conducted environmental surveys of our former Lafayette Facility located at the Lafayette Regional Airport, which we vacated in 2001, and determined that limited soil and groundwater contamination exist at two parcels of land at the former facility. An Assessment Report for both parcels was submitted in 2003 (and updated in 2006) to the Louisiana Department of Environmental Quality ("LDEQ") and the Louisiana Department of Natural Resources ("LDNR"). Approvals for the Assessment Report were received from the LDEQ and LDNR in 2010 and 2011, respectively. Since that time, we have performed groundwater sampling of the required groundwater monitor well installations at both parcels and submitted these sampling reports to the LDEQ. Pursuant to an agreement with the LDEQ, we provided groundwater sample results semi-annually to the LDEQ for both parcels from 2005 to 2015. The LDEQ approved a reduction in the sampling program from semi-annual to annual groundwater monitoring in 2015. Based on our working relationship and agreements with the LDEQ, and the results of ongoing former facility parcel monitoring, we believe that ultimate remediation costs for the subject parcels will not be material to our consolidated financial position, operations or cash flows. Legal Matters – From time to time, we are involved in various legal actions incidental to our business, including actions relating to employee claims, medical malpractice claims, tax issues, grievance hearings before labor regulatory agencies, and miscellaneous third party tort actions. The outcome of these proceedings is not predictable. However, based on current circumstances, we do not believe that the ultimate resolution of our presently pending proceedings, after considering available defenses and any insurance coverage or indemnification rights, will have a material adverse effect on our financial position, results of operations or cash flows. Operating Leases – We lease certain aircraft, facilities, and equipment used in our operations. The related lease agreements, which include both non-cancelable and month-to-month terms, generally provide for fixed monthly rentals, and certain real estate leases also include renewal options. We generally pay all insurance, taxes, and maintenance expenses associated with these leases. At September 30, 2018 , we had approximately $173.2 million in aggregate commitments under operating leases of which approximately $11.0 million is payable through the fourth quarter of 2018. The total lease commitments include $154.1 million for aircraft and $19.1 million for facility lease commitments. As of September 30, 2018, we had options to purchase aircraft under leases, with such purchase options becoming exercisable in 2019 and 2020. The aggregate option purchase prices are $129.0 million in 2019, and $22.7 million in 2020. Under current conditions, we believe it is unlikely that we will exercise the purchase options arising over the next year, unless opportunistic conditions arise. A majority of our aircraft operating leases contain financial covenants that are substantially similar to the financial covenants that were contained in our revolving credit facility at the time the leases were entered into. We have solicited and received amendments and waivers of certain covenants in some of these leases. We remain in active discussions with our aircraft lessors to resolve open issues and pursue any additional waivers or amendments that may be required, but cannot assure you that these efforts will be successful. Generally in the event of a default, the applicable lessor has the option of terminating the lease and requiring the return of the leased aircraft, with the repayment of any arrears of lease payments plus additional damages which may include the present value of all future lease payments and certain other amounts which could be material to our financial position. Defaults caused by payment failures or resulting in the acceleration of payment obligations would constitute an event of default under our senior notes if they involve sums in an aggregate amount in excess of $20 million. Our term loan and many of our operating leases contain similar cross-default or cross-acceleration provisions. Thus, our failure to meet the financial covenants in our operating lease agreements could ultimately result in the acceleration of significant obligations under other of our finance or lease instruments

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL Our Goodwill represents the amount by which our purchase price for the HNZ Offshore Business exceeded the fair value of net assets acquired. Goodwill has an indefinite useful life and is not amortized. We test goodwill for impairment annually as of October 1st or when events or changes in circumstances indicate that a potential impairment exists. Goodwill of $61.3 million as of September 30, 2018 and December 31, 2017 was as follows: Oil & Gas Air Medical Technical Services Total Balance December 31, 2017 $ 61,299 — — $ 61,299 Activity — — — — Balance September 30, 2018 $ 61,299 — — $ 61,299

Other Intangible Assets

Other Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets	OTHER INTANGIBLE ASSETS Intangible assets with finite useful lives are amortized over estimated useful lives on a straight-line basis. Our intangible assets, which arose in connection with our acquisition of the HNZ Offshore Business, consist of the following (in thousands): Estimated Useful Lives Gross Amount at December 31, 2017 Accumulated Amortization Net Balance at September 30, 2018 Customer Relationship 15 $ 11,622 $ (581 ) $ 11,041 Non-Compete Agreements 5 900 (135 ) 765 Trade Names 7 4,201 (450 ) 3,751 Total $ 16,723 $ (1,166 ) $ 15,557 Based on the carrying values of our intangible assets at September 30, 2018 , we estimate our amortization expense for the next five years (2018 through 2022) to be $1.6 million per year. For the quarter and nine months ended September 30, 2018 , amortization expense was $0.4 million and $1.2 million , respectively.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION PHI is primarily a provider of helicopter transport services, including helicopter maintenance and repair services. We report our financial results through the three reportable segments further described below. A segment’s operating profit or loss is its operating revenues less its direct expenses and selling, general and administrative expenses. Each segment has a portion of selling, general and administrative expenses that is charged directly to the segment, and a small portion that is allocated. Direct charges represent the vast majority of segment selling, general and administrative expenses. Allocated selling, general and administrative expenses are based primarily on total segment costs as a percentage of total operating costs. A significant portion of our selling, general and administrative expenses are neither charged nor allocated to our segments. Oil and Gas Segment - Our Oil and Gas segment, headquartered in Lafayette, Louisiana, provides helicopter services primarily for the major integrated and independent oil and gas production companies transporting personnel or equipment to offshore platforms in the Gulf of Mexico and a number of foreign countries. Our customers include Shell Oil Company, BP America Production Company, ExxonMobil Production Company, and ConocoPhillips Company, with whom we have worked for 35 or more years, and ENI Petroleum, with whom we have worked for more than 20 years. At September 30, 2018 , we had available for use 126 aircraft in this segment. Our fixed-term contracts typically have original terms of one year to seven years (subject to provisions permitting early termination upon relatively short notice by the customers), with payment in U.S. dollars. For the quarters ended September 30, 2018 and 2017 , respectively, approximately 55% and 50% of our total operating revenues were generated by our Oil and Gas segment, with approximately 85% and 89% of these revenues from fixed-term customer contracts. For the nine months ended September 30, 2018 and 2017, respectively, approximately 57% and 51% of our total operating revenues were generated by our Oil and Gas segment, with approximately 87% and 90% of these revenues from fixed-term customer contracts. The remaining 13% and 10% of these revenues were attributable to work in the spot market and ad hoc flights for contracted customers. Air Medical Segment - The operations of our Air Medical segment are headquartered in Phoenix, Arizona, where we maintain significant separate facilities and administrative staff dedicated to this segment. We provide Air Medical transportation services for hospitals and emergency service agencies throughout the U.S. As of September 30, 2018 , our Air Medical segment operated approximately 108 aircraft in 18 states at 80 separate locations. For the quarters ended September 30, 2018 and 2017, approximately 42% and 47% of our total operating revenues were generated by our Air Medical segment, respectively. For the nine months ended September 30, 2018 and 2017, approximately 39% and 45% of our total operating revenues were generated by our Air Medical segment. Estimates regarding the payor mix and changes in reimbursement rates are the factors most subject to sensitivity and variability in calculating our allowances. We compute a historical payment analysis of accounts fully closed, by category. Provisions for contractual discounts and estimated uncompensated care for our Air Medical segment (expressed as a percentage of gross segment billings) were as follows for the periods listed below: Quarter Ended Nine Months Ended 2018 2017 2018 2017 Provision for contractual discounts 65 % 65 % 66 % 66 % Provision for uncompensated care 10 % 6 % 8 % 7 % These percentages are affected by various factors, including rate increases and changes in the number of transports by payor mix. Net reimbursement per transport from commercial payors generally increases when a rate increase is implemented. Net reimbursement from certain commercial payors, as well as Medicare and Medicaid, generally does not increase proportionately with rate increases. Net revenue attributable to Insurance, Medicare, Medicaid, and Self-Pay (expressed as a percentage of net Air Medical revenues) were as follows for the periods listed below: Quarter Ended Nine Months Ended 2018 2017 2018 2017 Insurance 70 % 73 % 71 % 72 % Medicare 20 % 17 % 20 % 18 % Medicaid 9 % 9 % 8 % 9 % Self-Pay 1 % 1 % 1 % 1 % We also have a limited number of contracts with hospitals under which we receive a fixed fee component for aircraft availability and a variable fee component for flight time. Most of our contracts with hospitals contain provisions permitting early termination by the hospital, typically with 180 days’ notice for any reason and generally with penalty. Those contracts generated approximately 17% and 15% of the segment’s revenues for the quarters ended September 30, 2018 and 2017 , respectively. For the nine months ended September 30, 2018 and 2017, these contracts generated approximately 17% of the segment's revenues. We also derive a small portion of the segment’s revenues from providing services under our patient navigation business. Technical Services Segment - Our Technical Services segment provides helicopter repair and overhaul services for flight operations customers that own their aircraft. Costs associated with these services are primarily labor, and customers are generally billed at a percentage above our service costs. We also periodically provide flight services to governmental customers under this segment, including our current agreement to operate six aircraft for the National Science Foundation in Antarctica, typically in the first and fourth quarters each year. Also included in this segment are our proprietary Helipass operations, which provide software as a service to certain of our Oil and Gas customers for the purpose of passenger check-in and compliance verification. For each of the quarters ended September 30, 2018 and 2017, approximately 3% of our total operating revenues were generated by our Technical Services segment. For each of the nine month periods ended September 30, 2018 and 2017, approximately 4% of our total operating revenues were generated by our Technical Services segment. Summarized financial information concerning our reportable operating segments for the quarters and nine months ended September 30, 2018 and 2017 is as follows: Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) (Thousands of dollars) Segment operating revenues Oil and Gas $ 93,338 $ 75,700 $ 286,046 $ 222,098 Air Medical 70,192 70,280 194,331 192,840 Technical Services 5,257 4,187 18,023 16,271 Total operating revenues, net 168,787 150,167 498,400 431,209 Segment direct expenses (1) (2) Oil and Gas (1) 94,832 81,467 285,818 236,878 Air Medical 60,358 51,120 170,966 152,363 Technical Services 4,892 3,761 14,563 12,565 Total direct expenses 160,082 136,348 471,347 401,806 Segment selling, general and administrative expenses Oil and Gas 4,321 1,148 13,642 4,501 Air Medical 3,666 3,136 10,087 9,280 Technical Services 356 338 1,066 1,032 Total segment selling, general and administrative expenses 8,343 4,622 24,795 14,813 Total segment direct and selling, general and administrative expenses 168,425 140,970 496,142 416,619 Net segment (loss) profit Oil and Gas (5,815 ) (6,915 ) (13,414 ) (19,281 ) Air Medical 6,168 16,024 13,278 31,197 Technical Services 9 88 2,394 2,674 Total net segment profit 362 9,197 2,258 14,590 Other, net (3) 1,845 710 (272 ) 2,471 Unallocated selling, general and administrative costs (1) (4) (7,912 ) (6,779 ) (21,404 ) (23,878 ) Interest expense (8,357 ) (8,027 ) (24,894 ) (24,305 ) (Loss) earnings before income taxes $ (14,062 ) $ (4,899 ) $ (44,312 ) $ (31,122 ) (1) Included in direct expenses and unallocated selling, general, and administrative costs are the depreciation and amortization expense amounts below: Depreciation and Amortization Expense Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Segment Direct Expense: Oil and Gas $ 13,175 $ 9,615 $ 36,444 $ 29,301 Air Medical 5,274 4,885 16,989 15,581 Technical Services 128 146 415 440 Total $ 18,577 $ 14,646 $ 53,848 $ 45,322 Unallocated SG&A $ 2,366 $ 1,936 $ 5,693 $ 5,271 (2) Includes equity in (earnings) of unconsolidated affiliates, net. (3) Consists of (gains) losses on disposition of property and equipment and other income. (4) Represents corporate overhead expenses not allocable to segments.

Investment in Variable Interest

Investment in Variable Interest Entity	9 Months Ended
	Sep. 30, 2018
Investment in Variable Interest Entity and Other Investments and Affiliates [Abstract]
Investment in Variable Interest Entity	INVESTMENT IN VARIABLE INTEREST ENTITY We account for our investment in PHI Century Limited ("PHIC") as a variable interest entity, which is defined as an entity that either (a) has insufficient equity to permit the entity to finance its operations without additional subordinated financial support or (b) has equity investors who lack the characteristics of a controlling financial interest. As of September 30, 2018 , we had a 49% investment in the common stock of PHIC, a Ghanaian entity. We acquired our 49% interest on May 26, 2011 , PHIC’s date of incorporation. The purpose of PHIC is to provide oil and gas flight services in Ghana and the West African region. For the quarter ended September 30, 2018 , we recorded gain in equity of this unconsolidated affiliate of $0.1 million compared to loss in equity of $0.1 million for the quarter ended September 30, 2017 relative to our 49% equity ownership. For the nine months ended September 30, 2018 and 2017, we recorded a gain in equity of this unconsolidated affiliate of less than $0.2 million and a loss of $1.0 million relative to our 49% equity ownership, respectively. We had $4.4 million and $4.0 million of trade receivables from PHIC as of September 30, 2018 and December 31, 2017 , respectively. During the nine months ended September 30, 2018 , we loaned PHIC $0.4 million for operating purposes. This loan balance is included in Accounts receivable - other on our Condensed Consolidated Balance Sheets at September 30, 2018 . Our investment in the common stock of PHIC is included in Other Assets on our Condensed Consolidated Balance Sheets and was $0.5 million at September 30, 2018 and $0.3 million at December 31, 2017 .

Other Comprehensive Income

Other Comprehensive Income	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Other Comprehensive Income	OTHER COMPREHENSIVE INCOME Amounts reclassified from Accumulated other comprehensive income are not material and, therefore, not presented separately in the Condensed Consolidated Statements of Comprehensive Income.

Condensed Consolidating Financi

Condensed Consolidating Financial Information	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Financial Information	CONDENSED CONSOLIDATING FINANCIAL INFORMATION As discussed further in Note 5, on March 17, 2014, PHI, Inc. issued $500.0 million aggregate principal amount of 5.25% Senior Notes due 2019 that are fully and unconditionally guaranteed on a joint and several, senior basis by all of PHI, Inc.’s domestic subsidiaries. PHI, Inc. directly or indirectly owns 100% of all of its domestic subsidiaries. The supplemental condensed financial information on the following pages sets forth, on a consolidated basis, the balance sheet, statement of operations, statement of comprehensive income, and statement of cash flows information for PHI, Inc. (“Parent Company”) the guarantor subsidiaries and the non-guarantor subsidiaries, each under separate headings. The eliminating entries eliminate investments in subsidiaries, intercompany balances, and intercompany revenues and expenses. The condensed consolidating financial statements have been prepared on the same basis as the consolidated financial statements of PHI, Inc. The equity method is followed by the Parent Company within the financial information presented below. The transactions reflected in “Due to/from affiliates, net” in the following condensed consolidated statements of cash flows primarily consist of centralized cash management activities between PHI, Inc. and its subsidiaries, pursuant to which cash earned by the guarantor subsidiaries is regularly transferred to PHI, Inc. to be centrally managed. Because these balances are treated as short-term borrowings of the Parent Company, serve as a financing and cash management tool to meet our short-term operating needs, turn over quickly and are payable to the guarantor subsidiaries on demand, we present borrowings and repayments with our affiliates on a net basis within the condensed consolidating statement of cash flows. Net receivables from our affiliates are considered advances and net payables to our affiliates are considered borrowings, and both changes are presented as financing activities in the following condensed consolidating statements of cash flows. See "-Other" in Note 5. PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS (Thousands of dollars) (Unaudited) September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS Current Assets: Cash $ 9,905 $ 1,880 $ 4,668 $ — $ 16,453 Short-term investments 30,509 — — — 30,509 Accounts receivable – net 75,970 95,340 29,574 (3,477 ) 197,407 Intercompany receivable — 92,338 — (92,338 ) — Inventories of spare parts – net 60,914 10,646 2,792 — 74,352 Prepaid expenses 9,364 2,640 1,197 — 13,201 Income taxes receivable 139 510 — — 649 Total current assets 186,801 203,354 38,231 (95,815 ) 332,571 Investment in subsidiaries 415,980 — — (415,980 ) — Property and equipment – net 598,363 286,015 39,199 — 923,577 Restricted cash and investments 19,781 — — — 19,781 Other assets 140,265 1,042 (131,165 ) — 10,142 Deferred income tax — — 1,009 — 1,009 Goodwill — — 61,299 — 61,299 Intangible assets — — 15,557 — 15,557 Total assets $ 1,361,190 $ 490,411 $ 24,130 $ (511,795 ) $ 1,363,936 LIABILITIES AND SHAREHOLDERS’ EQUITY Current Liabilities: Short-term debt $ 499,429 $ — $ — $ — $ 499,429 Accounts payable 32,458 5,200 5,028 (3,477 ) 39,209 Accrued and other current liabilities 18,781 14,053 6,723 — 39,557 Intercompany payable 81,384 — 10,954 (92,338 ) — Total current liabilities 632,052 19,253 22,705 (95,815 ) 578,195 Long-term debt 129,126 — — — 129,126 Deferred income taxes and other long-term liabilities 18,536 57,439 3,255 — 79,230 Shareholders’ Equity: Common stock and paid-in capital 314,085 77,952 1,510 (79,462 ) 314,085 Accumulated other comprehensive loss (3 ) — (4,091 ) — (4,094 ) Retained earnings 267,394 335,767 751 (336,518 ) 267,394 Total shareholders’ equity 581,476 413,719 (1,830 ) (415,980 ) 577,385 Total liabilities and shareholders’ equity $ 1,361,190 $ 490,411 $ 24,130 $ (511,795 ) $ 1,363,936 PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS (Thousands of dollars) December 31, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS Current Assets: Cash $ 47 $ 1,072 $ 7,651 $ — $ 8,770 Short-term investments 64,237 — — — 64,237 Accounts receivable – net 90,077 74,886 38,020 (17,004 ) 185,979 Intercompany receivable — 126,366 — (126,366 ) — Inventories of spare parts – net 68,737 9,049 3,095 — 80,881 Prepaid expenses 8,348 1,898 1,229 — 11,475 Income taxes receivable 345 9 917 — 1,271 Total current assets 231,791 213,280 50,912 (143,370 ) 352,613 Investment in subsidiaries and others 397,301 — — (397,301 ) — Property and equipment – net 617,488 284,984 44,293 — 946,765 Restricted investments 12,382 — 14 — 12,396 Other assets 139,754 908 (131,921 ) — 8,741 Deferred income tax — — 3,309 — 3,309 Goodwill — — 61,299 — 61,299 Intangible assets — — 16,723 — 16,723 Total assets $ 1,398,716 $ 499,172 $ 44,629 $ (540,671 ) $ 1,401,846 LIABILITIES AND SHAREHOLDERS’ EQUITY Current Liabilities: Accounts payable $ 28,130 $ 4,636 $ 21,425 $ (17,005 ) $ 37,186 Accrued and other current liabilities 23,147 10,577 8,126 — 41,850 Intercompany payable 113,387 — 12,978 (126,365 ) — Total current liabilities 164,664 15,213 42,529 (143,370 ) 79,036 Long-term debt 615,994 — — — 615,994 Deferred income taxes and other long-term liabilities 5,404 84,300 4,458 — 94,162 Shareholders’ Equity: Common stock and paid-in capital 309,933 77,951 1,375 (79,326 ) 309,933 Accumulated other comprehensive loss (280 ) — — — (280 ) Retained earnings 303,001 321,708 (3,733 ) (317,975 ) 303,001 Total shareholders’ equity 612,654 399,659 (2,358 ) (397,301 ) 612,654 Total liabilities and shareholders’ equity $ 1,398,716 $ 499,172 $ 44,629 $ (540,671 ) $ 1,401,846 PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) (Unaudited) For the Quarter Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 75,654 $ 72,396 $ 22,027 $ (1,290 ) $ 168,787 Expenses: Direct expenses 83,935 62,045 15,510 (1,290 ) 160,200 Selling, general and administrative expenses 9,987 3,666 2,606 (4 ) 16,255 Total operating expenses 93,922 65,711 18,116 (1,294 ) 176,455 Gain on disposal of assets, net — — — — — Equity in income of unconsolidated affiliates, net (118 ) — — — (118 ) Operating (loss) income (18,150 ) 6,685 3,911 4 (7,550 ) Equity in net income of consolidated subsidiaries (10,381 ) — — 10,381 — Interest expense 8,356 1 — — 8,357 Other income, net (301 ) — (1,548 ) 4 (1,845 ) (2,326 ) 1 (1,548 ) 10,385 6,512 (Loss) earnings before income taxes (15,824 ) 6,684 5,459 (10,381 ) (14,062 ) Income tax (benefit) expense (4,293 ) — 1,762 — (2,531 ) Net (loss) earnings $ (11,531 ) $ 6,684 $ 3,697 $ (10,381 ) $ (11,531 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) For the Quarter Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 79,644 $ 70,692 $ 7,784 $ (7,953 ) $ 150,167 Expenses: Direct expenses 83,727 51,247 9,765 (7,953 ) 136,786 Selling, general and administrative expenses 8,240 3,141 24 (4 ) 11,401 Total operating expenses 91,967 54,388 9,789 (7,957 ) 148,187 Loss (gain) on disposal of assets, net (4 ) — — — (4 ) Equity in (income) loss of consolidated affiliate 112 — (550 ) — (438 ) Operating (loss) income (12,431 ) 16,304 (1,455 ) 4 2,422 Equity in net income of consolidated subsidiaries (14,850 ) — — 14,850 — Interest expense 8,027 — — — 8,027 Other income, net (709 ) (1 ) — 4 (706 ) (7,532 ) (1 ) — 14,854 7,321 (Loss) earnings before income taxes (4,899 ) 16,305 (1,455 ) (14,850 ) (4,899 ) Income tax (benefit) expense (1,622 ) — — — (1,622 ) Net (loss) earnings $ (3,277 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,277 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 233,608 $ 199,823 $ 68,065 $ (3,096 ) $ 498,400 Expenses: Direct expenses 246,888 175,673 52,045 (3,097 ) 471,509 Selling, general and administrative expenses 27,129 10,089 8,994 (13 ) 46,199 Total operating expenses 274,017 185,762 61,039 (3,110 ) 517,708 Loss (gain) on disposal of assets, net 729 — (21 ) — 708 Equity in income of unconsolidated affiliates, net (162 ) — — — (162 ) Operating (loss) income (40,976 ) 14,061 7,047 14 (19,854 ) Equity in net income of consolidated subsidiaries (18,542 ) — — 18,542 — Interest expense 24,888 2 4 — 24,894 Other income, net (359 ) — (91 ) 14 (436 ) 5,987 2 (87 ) 18,556 24,458 (Loss) earnings before income taxes (46,963 ) 14,059 7,134 (18,542 ) (44,312 ) Income tax (benefit) expense (11,356 ) — 2,651 — (8,705 ) Net (loss) earnings $ (35,607 ) $ 14,059 $ 4,483 $ (18,542 ) $ (35,607 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 228,973 $ 197,022 $ 15,987 $ (10,773 ) $ 431,209 Expenses: Direct expenses 238,669 155,434 16,920 (10,773 ) 400,250 Selling, general and administrative expenses 29,265 9,296 144 (14 ) 38,691 Total operating expenses 267,934 164,730 17,064 (10,787 ) 438,941 Loss (gain) on disposal of assets, net 4 (1 ) — — 3 Equity in loss of unconsolidated affiliate 1,040 — 516 — 1,556 Operating (loss) income (40,005 ) 32,293 (1,593 ) 14 (9,291 ) Equity in net income of consolidated subsidiaries (32,093 ) — — 32,093 — Interest expense 24,283 22 — — 24,305 Other income, net (2,486 ) (2 ) — 14 (2,474 ) (10,296 ) 20 — 32,107 21,831 (Loss) earnings before income taxes (29,709 ) 32,273 (1,593 ) (32,093 ) (31,122 ) Income tax (benefit) expense (7,911 ) (1,413 ) — — (9,324 ) Net (loss) earnings $ (21,798 ) $ 33,686 $ (1,593 ) $ (32,093 ) $ (21,798 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Quarter Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (11,531 ) $ 6,684 $ 3,697 $ (10,381 ) $ (11,531 ) Unrealized gain on short-term investments — — — — — Currency translation adjustments — — (4,718 ) — (4,718 ) Changes in pension plan asset and benefit obligation — — — — — Tax effect of the above-listed adjustments — — — — — Total comprehensive (loss) income $ (11,531 ) $ 6,684 $ (1,021 ) $ (10,381 ) $ (16,249 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) For the Quarter Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (3,277 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,277 ) Unrealized gain on short-term investments 41 — — — 41 Changes in pension plan asset and benefit obligations (24 ) — — — (24 ) Tax effect of the above-listed adjustments (8 ) — — — (8 ) Total comprehensive (loss) income $ (3,268 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,268 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (35,607 ) $ 14,059 $ 4,483 $ (18,542 ) (35,607 ) Unrealized gain on short-term investments 363 — — — 363 Currency translation adjustment — — (4,091 ) — (4,091 ) Changes in pension plan asset and benefit obligation (1 ) — — — (1 ) Tax effect of the above-listed adjustments (85 ) — — — (85 ) Total comprehensive (loss) income $ (35,330 ) $ 14,059 $ 392 $ (18,542 ) $ (39,421 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (21,798 ) $ 33,686 $ (1,593 ) $ (32,093 ) (21,798 ) Unrealized gain on short-term investments 370 — — — 370 Changes in pension plan asset and benefit obligations (2 ) — — — (2 ) Tax effect of the above-listed adjustments (134 ) — — — (134 ) Total comprehensive (loss) income $ (21,564 ) $ 33,686 $ (1,593 ) $ (32,093 ) $ (21,564 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net cash (used in) provided by operating activities $ (25,451 ) $ 6,439 $ 10,964 $ — $ (8,048 ) Investing activities: Purchase of property and equipment (20,580 ) — (2,181 ) — (22,761 ) Proceeds from asset dispositions 1,453 — — — 1,453 Purchase of short-term investments (284,277 ) — — — (284,277 ) Purchase of restricted investments (7,705 ) — — — (7,705 ) Proceeds from sale of short-term investments 318,007 — — — 318,007 Loan to unconsolidated affiliate (274 ) — — — (274 ) Net cash (used in) investing activities 6,624 — (2,181 ) — 4,443 Financing activities: Debt issuance costs (874 ) — — — (874 ) Proceeds from line of credit 34,295 — — — 34,295 Payments on line of credit (151,795 ) — — — (151,795 ) Proceeds from Term Loan 130,000 130,000 Due to/from affiliate, net 17,158 (5,631 ) (11,527 ) — — Repurchase of common stock (99 ) — — — (99 ) Net cash provided by (used in) financing activities 28,685 (5,631 ) (11,527 ) — 11,527 Effect of exchange rate changes on cash — — (239 ) — (239 ) Increase (decrease) in cash 9,858 808 (2,983 ) — 7,683 Cash, beginning of period 47 1,072 7,651 — 8,770 Cash, end of period $ 9,905 $ 1,880 $ 4,668 $ — $ 16,453 PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (Thousands of dollars) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net cash (used in) provided by operating activities $ (43,328 ) $ 33,670 $ 7,790 $ — $ (1,868 ) Investing activities: Purchase of property and equipment (49,227 ) — — — (49,227 ) Proceeds from asset dispositions 21 — — — 21 Purchase of short-term investments (268,525 ) — — (268,525 ) Proceeds from sale of short-term investments 354,250 — — 354,250 Payments of deposits on aircraft — — — — Net cash provided by investing activities 36,519 — — — 36,519 Financing activities: Proceeds from line of credit 99,150 — — — 99,150 Payments on line of credit (133,150 ) — — — (133,150 ) Repurchase of common stock (256 ) — — — (256 ) Due to/from affiliate, net 41,079 (34,699 ) (6,380 ) — — Net cash provided by (used in) financing activities 6,823 (34,699 ) (6,380 ) — (34,256 ) Increase (decreased) in cash 14 (1,029 ) 1,410 — 395 Cash, beginning of period 36 2,100 460 — 2,596 Cash, end of period $ 50 $ 1,071 $ 1,870 $ — $ 2,991

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements - In 2014, the Financial Accounting Standard Board ("the FASB") issued ASC 606, Revenue from Contracts with Customers (“ASC 606”), replacing the existing accounting standard and industry specific guidance for revenue recognition with a five-step model for recognizing and measuring revenue from contracts with customers. The underlying principle of the new standard is to recognize revenue to depict the transfer of goods or services to customers at the amount expected to be collected. ASC 606 became effective on January 1, 2018 and we adopted it using the modified retrospective method applied to open contracts and only to the version of the contracts in effect as of January 1, 2018. Prior period amounts have not been adjusted and continue to be reflected in accordance with our historical accounting. There was no impact on the condensed consolidated financial statements and no cumulative effect adjustment was recognized. In general, under ASC 606, we recognize revenue when a service or good is sold to a customer and there is a contract. At contract inception, we assess the goods and services promised in our contracts with customers and identify all performance obligations for each distinct promise that transfers a good or service (or bundle of goods or services) to the customer. To identify the performance obligations, we consider all goods or services promised in the contract, whether explicitly stated or implied based on customary business practices. Revenue is recognized when control of the identified distinct goods or services has been transferred to the customer, the transaction price has been determined and allocated to the performed performance obligations and we have determined that collection has occurred or is probable of occurring. We measure revenue as the amount of consideration we expect to receive in exchange for the services provided. Taxes collected from customers and remitted to governmental authorities and revenues are reported on a net basis in the our financial statements. Thus, we exclude taxes imposed on the customer and collected on behalf of governmental agencies to be remitted to these agencies from the transaction price in determining the revenue related to contracts with a customer. Oil & Gas Revenue Recognition - We provide helicopter services to oil and gas customers operating in the Gulf of Mexico and a number of foreign countries. Revenues are recognized when performance obligations are satisfied over time in accordance with contractual terms, in an amount that reflects the consideration the Company expects to be entitled to in exchange for services rendered. Air Medical Revenue Recognition - We provide helicopter services to hospitals and emergency service providers in several U.S. states, or to individual patients in the U.S. in which case we are paid by either a commercial insurance company, federal or state agency, or the patient. Our Air Medical segment operates primarily under the independent provider model and, to a lesser extent, under the traditional provider model. Revenues related to the independent provider model services are recorded in the period in which we satisfy our performance obligations under contracts by providing our services to our customers based upon established billing rates net of contractual allowances under agreements with third party payors and net of uncompensated care allowances. These amounts are due from patients, third-party payors (including health insurers and government programs), and others and includes variable consideration for retroactive revenue adjustments due to settlement of audits, reviews, and investigations. Generally, we bill the patients and third-party payors several days after the services are performed. Revenues generated under the traditional provider model are recognized as performance obligations are satisfied over time in accordance with contractual terms, in an amount that reflects the consideration the Company expects to be entitled in exchange for services rendered. Oil & Gas Performance Obligations - A performance obligation arises under contracts with customers to render services and is the unit of account under ASC 606. Operating revenue from our Oil and Gas segment is derived mainly from fixed-term contracts with our customers, a substantial portion of which are competitively bid. A small portion of our Oil and Gas segment revenue is derived from providing services on an "ad-hoc" basis. Our fixed-term contracts typically have original terms of one to seven years (subject to provisions permitting early termination on relatively short notice by the customers), with payment in U.S. dollars. We account for services rendered separately if they are distinct and the services are separately identifiable from other items provided to a customer and if a customer can benefit from the services rendered on its own or with other resources that are readily available to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. Within this contract type for helicopter services, we determined that each contract has a single distinct performance obligation. These services include a fixed monthly rate for a particular model of aircraft, and flight hour services, which represents the variable component of a typical contract with a customer. Rates for these services vary depending on the type of services provided and can be based on a per flight hour, per day, or per month basis. We also provide services to clients on an “ad hoc” basis, which usually entails a shorter contract notice period and duration. The charges for ad hoc services are based on an hourly rate or a daily or monthly fixed fee plus additional fees for each hour flown. The nature of our variable charges within our flight services contracts are not effective until a customer-initiated flight order and the actual hours flown are determined; therefore, the associated flight revenue generally cannot be reasonably and reliably estimated before hand. A contract’s standalone selling prices are determined based upon the prices that we charge for our services rendered. The majority of our revenue is recognized as performance obligations satisfied over time, by measuring progress towards satisfying the contracted services in a manner that best depicts the transfer of services to the customer, which is generally represented by a period of 30 days or less. We typically invoice customers on a monthly basis with the term between invoicing and when the payment is due typically being between 30 and 60 days. Air Medical Performance Obligations - Performance obligations are determined based upon the nature of the services provided. Under the independent provider model, we measure the performance obligation from the moment the patient is loaded into the aircraft until it reaches its destination. Under this model, we have no fixed revenue stream and compete for transport referrals on a daily basis with other independent operators in the area. As an independent provider, we bill for our services on the basis of a flat rate plus a variable charge per patient-loaded mile, regardless of aircraft model, and are typically compensated by private insurance, Medicaid or Medicare, or directly by transported patients who self-pay. We recognize revenues for performance obligations satisfied at a point in time, which generally relate to patients receiving air medical services when: (1) services are provided; and (2) we do not believe the patient requires additional services. For the independent provider model, we determine the transaction price based upon gross charges for services provided reduced by contractual adjustments provided to third-party payors, discounts provided to uninsured patients in accordance with Company policy, and/or implicit price concessions provided to uninsured patients. We determine estimates of contractual adjustments and discounts based upon contractual agreements, our discount policy, and historical experience. We determine our estimate of implicit price concessions based upon our historical collection experience with these classes of patients using a portfolio approach as a practical expedient to account for patient contracts as collective groups, rather than individually. The financial statement effects of using this practical expedient are not materially different from an individual contract approach. Under the traditional provider model, we contract directly with the customer to provide their transportation services. These contracts are typically awarded or renewed through competitive bidding and typically permit early termination by the customer on relatively short notice. As a traditional provider, we typically bill a fixed monthly rate for aircraft availability and an hourly rate for flight time. For each of these types of helicopter services, we have determined that each has a single distinct performance obligation. Traditional provider models services include fixed monthly rate for a particular model of aircraft, and flight hour services, which represents the variable component of a typical contract with a customer. Rates for these services vary depending on the type of services provided and can be based on a per flight hour, per day, or per month basis. The variable charges within such contracts are not effective until the customer initiates a flight order and the actual hours flown are determined; therefore, the associated revenue generally cannot be reasonably and reliably estimated beforehand. For the traditional provider model, we determine the transaction price based upon standard charges for goods and services provided. As further described in Note 3, independent provider revenues are recorded net of contractual allowances under agreements with third party payors and estimated uncompensated care at the time the services are provided. Contractual allowances and uncompensated care are estimated based on historical collection experience by payor category (consisting mainly of private insurance, Medicaid, Medicare, and self-pay). The allowance percentages calculated are applied to the payor categories, and the necessary adjustments are made to the revenue allowance. Agreements with third-party payors typically provide for payments at amounts less than established charges. As of September 30, 3018 and December 31, 2017, receivables related to our (i) Oil and Gas segment were $103.1 million and $106.8 million , (ii) Air Medical segment were $91.8 million and $74.4 million and (iii) Technical Services segment were $2.5 million and $4.8 million , respectively. Contract assets and contract liabilities were immaterial as of September 30, 2018. Our contracts typically include termination clauses that allow both parties to terminate existing contracts with a 30 to 180 day notice period. We generally have a right to consideration in an amount that corresponds directly with the value to the customer of the entity's performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. We have elected to use the invoice practical expedient for revenue recognized when performance obligations are satisfied over time. In addition, payment for goods and services rendered is typically due in the subsequent month following satisfaction of our performance obligation. Our Technical Services segment provides helicopter flight services and helicopter repair and overhaul services for existing flight operations customers that own their own aircraft. Under this segment, we periodically provide certain services to governmental customers, including our agreement to operate six aircraft for the National Science Foundation in Antarctica. Under this segment, we also offer certain software as a service to our Oil and Gas customers. Revenues are recognized when performance obligations are satisfied in accordance with contractual terms, in an amount that reflects the consideration we expect to be entitled to in exchange for services rendered. For these helicopter services, we determined that each has a single distinct performance obligation. The following table presents the Company’s revenues by segment disaggregated by type (in thousands): For the Quarter Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Service Revenue Oil & Gas $ 93,338 $ 75,700 $ 286,046 $ 222,098 Air Medical 70,192 70,280 194,331 192,840 Technical Services 5,257 4,187 18,023 16,271 Total Services $ 168,787 $ 150,167 $ 498,400 $ 431,209 Air Medical Revenue Traditional provider model $ 12,414 $ 11,816 $ 36,371 $ 35,427 Independent provider model 57,778 58,464 157,960 157,413 Total Air Medicals Revenues $ 70,192 $ 70,280 $ 194,331 $ 192,840 On January 26, 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) : Simplifying the Test for Goodwill Impairment (ASU 2017-04). ASU 2017-04 removes the requirement to compare the implied fair value of goodwill with the carrying amount as part of Step 2 of the goodwill impairment test. Under the new standard, the goodwill impairment loss will be measured as the excess of a reporting unit's carrying amount over its fair value, not exceeding the total amount of goodwill allocated to that reporting unit, which may increase the frequency of goodwill impairment charges if a future goodwill impairment test does not pass the Step 1 evaluation. ASU 2017-04 is effective prospectively for periods beginning on or after December 15, 2019, with early adoption permitted. We adopted ASU 2017-04 effective January 1, 2018. We will perform goodwill impairment testing under the new standard annually as of October 1st or when events or changes in circumstances indicate that a potential impairment exist. In November 2015, the FASB issued ASU 2015-17, Balance Sheet Classification of Deferred Taxes , which requires that deferred tax assets and liabilities be classified as noncurrent in a classified balance sheet. We adopted this ASU in the fourth quarter of 2017 on a prospective basis. Beginning with the December 31, 2017 balances, all deferred taxes were classified as non-current. Periods prior to December 31, 2017 were not retrospectively adjusted. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other than Inventory , which will require an entity to recognize the income tax consequences of an intra-entity transfer of an asset, other than inventory, when the transfer occurs. The ASU is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods. We adopted ASU 2016-16 effective January 1, 2018 with no material impact to the condensed consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business . ASU 2017-01 clarifies the definition of a business and requires that an entity apply certain criteria in order to determine when a set of assets and activities qualifies as a business. The adoption of this standard is expected to result in fewer acquisitions of properties qualifying as acquisitions of businesses and, accordingly, acquisition costs for those acquisitions that do not qualify as businesses will be capitalized rather than expensed. This standard is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, and should be applied on a prospective basis. We adopted ASU 2017-01 effective January 1, 2018 with no material impact to the condensed consolidated financial statements. On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was enacted which significantly reformed the U.S. Internal Revenue Code (the “Code”). The Tax Act, among other things, reduced the federal corporate income tax rate from 35% to 21% effective January 1, 2018. Following the enactment of the Tax Act, the SEC staff issued Staff Accounting Bulletin 118 - "Income Tax Accounting Implications of the Tax Cuts and Jobs Act" (SAB 118), which provides for a measurement period of up to one year from the enactment date to complete accounting under GAAP for the tax effects of the legislation. As of December 31, 2017, we had not completed its accounting for the tax effects of the Tax Act, but did remeasure its net deferred tax liability at December 31, 2017 and provisionally recognized a net benefit of $49.2 million in its consolidated statement of operations for the year ended December 31, 2017. As of September 30, 2018, we had not completed its accounting for the tax effects of the Tax Act and had not recorded any adjustments to the original provisional estimate. Although it does not anticipate any material adjustments related to the Tax Act, we will continue analyzing certain aspects of the Tax Act and refining its calculations, which could potentially affect the measurement of these balances or potentially give rise to changes to its current provisional estimates. Our estimates may be affected by a wide variety of factors, including additional regulatory guidance issued with respect to the Tax Act. In accordance with SAB 118, any subsequent adjustments to our provisional estimate will be recorded in the 4th quarter of 2018. New Accounting Pronouncements - In February 2016, the FASB issued ASU 2016-02, Leases , which replaces the existing guidance on leasing transactions in ASC 840 to require recognition of the assets and liabilities for the rights and obligations created by those leases on the balance sheet. We have formed an implementation team that is inventorying leases under ASC 840 and contracts which may be leases under ASC 842, and evaluating the impact that adoption of this guidance will have on the Company’s financial statements, which includes monitoring industry specific developments including recent exposure drafts issued by the FASB. The Company is continuing work to complete the implementation of an information technology system to track and account for its leases and of changes to its internal controls and accounting policies to support the accounting for leases under ASU 2016-02. Based on our lease portfolio as of September 30, 2018, we expect the adoption of this standard will result in a material change to our consolidated assets and liabilities. We plan to adopt this standard beginning January 1, 2019.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Disaggregated Revenues by Segment	The following table presents the Company’s revenues by segment disaggregated by type (in thousands): For the Quarter Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Service Revenue Oil & Gas $ 93,338 $ 75,700 $ 286,046 $ 222,098 Air Medical 70,192 70,280 194,331 192,840 Technical Services 5,257 4,187 18,023 16,271 Total Services $ 168,787 $ 150,167 $ 498,400 $ 431,209 Air Medical Revenue Traditional provider model $ 12,414 $ 11,816 $ 36,371 $ 35,427 Independent provider model 57,778 58,464 157,960 157,413 Total Air Medicals Revenues $ 70,192 $ 70,280 $ 194,331 $ 192,840

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Components of Investments	Investments consisted of the following as of September 30, 2018 : Cost Basis Unrealized Unrealized Fair (Thousands of dollars) Investments: Money market mutual funds $ 50,290 $ — $ — $ 50,290 Deferred compensation plan assets included in other assets 852 — — 852 Total $ 51,142 $ — $ — $ 51,142 Investments consisted of the following as of December 31, 2017 : Cost Basis Unrealized Gains Unrealized Losses Fair Value (Thousands of dollars) Investments: Money market mutual funds $ 5,601 $ — $ — $ 5,601 U.S. government agencies 7,501 — (34 ) 7,467 Corporate bonds and notes 63,880 — (330 ) 63,550 Subtotal 76,982 — (364 ) 76,618 Deferred compensation plan assets included in other assets 2,685 — — 2,685 Total $ 79,667 $ — $ (364 ) $ 79,303
Cost and Fair Value of Debt Investments Based on Maturities	The following table presents the cost and fair value of our debt investments based on maturities as of: September 30, 2018 December 31, 2017 Amortized Fair Amortized Fair (Thousands of dollars) Due in one year or less $ — $ — $ 31,348 $ 31,254 Due within two years — — 40,032 39,763 Total $ — $ — $ 71,380 $ 71,017
Average Coupon Rate Percentage and Average Days to Maturity of Debt	The following table presents the average coupon rate percentage and the average days to maturity of our debt investments as of: September 30, 2018 December 31, 2017 Average Average Average Average U.S. Government agencies — 0 1.370 370 Corporate bonds and notes — 0 1.766 392
Investments in Continuous Unrealized Loss Position for Less Than Twelve Months	The following table presents the fair value and unrealized losses related to our investments that have been in a continuous unrealized loss position for less than twelve months as of: September 30, 2018 December 31, 2017 Fair Value Unrealized Fair Value Unrealized (Thousands of dollars) U.S. Government agencies $ — $ — $ 5,472 $ (28 ) Corporate bonds and notes — — 44,069 (271 ) Total $ — $ — $ 49,541 $ (299 )
Investments in Continuous Unrealized Loss Position for More Than Twelve Months	The following table presents the fair value and unrealized losses related to our investments that have been in a continuous unrealized loss position for more than twelve months as of: September 30, 2018 December 31, 2017 Fair Value Unrealized Fair Value Unrealized (Thousands of dollars) U.S. Government agencies $ — $ — $ 1,994 $ (6 ) Corporate bonds and notes — — 19,482 (59 ) Total $ — $ — $ 21,476 $ (65 )

Valuation Accounts (Tables)

Valuation Accounts (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue Recognition And Valuation Accounts [Abstract]
Schedule of Allowance for Contractual Discounts and Estimated Uncompensated Care as a Percentage of Gross Segment Accounts Receivable	The allowance for contractual discounts and estimated uncompensated care (expressed as a percentage of gross segment accounts receivable) as of the dates listed below was as follows: September 30, 2018 December 31, 2017 Allowance for Contractual Discounts 48% 53% Allowance for Uncompensated Care 26% 24%

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Valuation of Investments and Financial Instruments Pricing Levels	The following table summarizes the valuation of our investments and financial instruments by the above pricing levels as of the valuation dates listed: September 30, 2018 Total (Level 1) (Level 2) (Thousands of dollars) Investments: Money market mutual funds $ 50,290 $ 50,290 $ — Deferred compensation plan assets 852 852 — Total $ 51,142 $ 51,142 $ — December 31, 2017 Total (Level 1) (Level 2) (Thousands of dollars) Investments: Money market mutual funds $ 5,601 $ 5,601 $ — U.S. government agencies 7,467 — 7,467 Corporate bonds and notes 63,550 — 63,550 76,618 5,601 71,017 Deferred compensation plan assets 2,685 2,685 — Total $ 79,303 $ 8,286 $ 71,017

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Components of Debt	Listed below is information regarding our indebtedness. All indebtedness owed under our Senior Notes as of September 30, 2018 is classified as short-term debt on our balance sheet as of such date. September 30, 2018 December 31, 2017 Principal Unamortized Principal Unamortized (Thousands of dollars) Senior Notes issued March 17, 2014, interest only payable semi-annually at 5.25%, maturing March 15, 2019 $ 500,000 $ 571 $ 500,000 $ 1,506 Revolving Credit Facility due March 7, 2019 with a group of commercial banks, interest payable at variable rates — — 117,500 — Related Party Term Loan - Thirty Two L.L.C., interest payable quarterly at 6%, due September 28, 2020 $ 130,000 $ 874 $ — $ — Total indebtedness $ 630,000 $ 1,445 $ 617,500 $ 1,506

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Components of Basic and Diluted Earnings Per Share	The components of basic and diluted earnings per share for the quarter and nine months ended September 30, 2018 and 2017 are as follows: Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Weighted average outstanding shares of common stock, basic 15,816 15,799 15,811 15,750 Dilutive effect of unvested restricted stock units — — — — Weighted average outstanding shares of common stock, diluted (1) 15,816 15,799 15,811 15,750 (1) For the quarters ended September 30, 2018 and 2017, 108,424 and - 0 - unvested restricted stock units were excluded from the weighted average outstanding shares of common stock, diluted, respectively, as they were anti-dilutive to earnings per share. For the nine months ended on both September 30, 2018 and 2017 , - 0 - unvested restricted stock units were excluded from the weighted average outstanding shares of common stock, diluted, as they were anti-dilutive to earnings per share.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Share Based Compensation Expense	The table below sets forth the total amount of stock-based compensation expense for the quarter and nine months ended September 30, 2018 and 2017 . Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Stock-based compensation expense: Time-based restricted stock units $ 1,085 $ 582 $ 2,162 $ 1,678 Performance-based restricted stock units 1,033 689 2,088 1,396 Total stock-based compensation expense $ 2,118 $ 1,271 $ 4,250 $ 3,074

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Goodwill of $61.3 million as of September 30, 2018 and December 31, 2017 was as follows: Oil & Gas Air Medical Technical Services Total Balance December 31, 2017 $ 61,299 — — $ 61,299 Activity — — — — Balance September 30, 2018 $ 61,299 — — $ 61,299

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Our intangible assets, which arose in connection with our acquisition of the HNZ Offshore Business, consist of the following (in thousands): Estimated Useful Lives Gross Amount at December 31, 2017 Accumulated Amortization Net Balance at September 30, 2018 Customer Relationship 15 $ 11,622 $ (581 ) $ 11,041 Non-Compete Agreements 5 900 (135 ) 765 Trade Names 7 4,201 (450 ) 3,751 Total $ 16,723 $ (1,166 ) $ 15,557

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of Provisions for Contractual Discounts and Estimated Uncompensated Care as a Percentage of Gross Segment Billings	Provisions for contractual discounts and estimated uncompensated care for our Air Medical segment (expressed as a percentage of gross segment billings) were as follows for the periods listed below: Quarter Ended Nine Months Ended 2018 2017 2018 2017 Provision for contractual discounts 65 % 65 % 66 % 66 % Provision for uncompensated care 10 % 6 % 8 % 7 %
Schedule of Net Revenue Attributable to Insurance, Medicare, Medicaid, and Self-Pay as Percentage of Net Air Medical Revenues	Net revenue attributable to Insurance, Medicare, Medicaid, and Self-Pay (expressed as a percentage of net Air Medical revenues) were as follows for the periods listed below: Quarter Ended Nine Months Ended 2018 2017 2018 2017 Insurance 70 % 73 % 71 % 72 % Medicare 20 % 17 % 20 % 18 % Medicaid 9 % 9 % 8 % 9 % Self-Pay 1 % 1 % 1 % 1 %
Schedule of Financial Information Concerning Reportable Operating Segments	Summarized financial information concerning our reportable operating segments for the quarters and nine months ended September 30, 2018 and 2017 is as follows: Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) (Thousands of dollars) Segment operating revenues Oil and Gas $ 93,338 $ 75,700 $ 286,046 $ 222,098 Air Medical 70,192 70,280 194,331 192,840 Technical Services 5,257 4,187 18,023 16,271 Total operating revenues, net 168,787 150,167 498,400 431,209 Segment direct expenses (1) (2) Oil and Gas (1) 94,832 81,467 285,818 236,878 Air Medical 60,358 51,120 170,966 152,363 Technical Services 4,892 3,761 14,563 12,565 Total direct expenses 160,082 136,348 471,347 401,806 Segment selling, general and administrative expenses Oil and Gas 4,321 1,148 13,642 4,501 Air Medical 3,666 3,136 10,087 9,280 Technical Services 356 338 1,066 1,032 Total segment selling, general and administrative expenses 8,343 4,622 24,795 14,813 Total segment direct and selling, general and administrative expenses 168,425 140,970 496,142 416,619 Net segment (loss) profit Oil and Gas (5,815 ) (6,915 ) (13,414 ) (19,281 ) Air Medical 6,168 16,024 13,278 31,197 Technical Services 9 88 2,394 2,674 Total net segment profit 362 9,197 2,258 14,590 Other, net (3) 1,845 710 (272 ) 2,471 Unallocated selling, general and administrative costs (1) (4) (7,912 ) (6,779 ) (21,404 ) (23,878 ) Interest expense (8,357 ) (8,027 ) (24,894 ) (24,305 ) (Loss) earnings before income taxes $ (14,062 ) $ (4,899 ) $ (44,312 ) $ (31,122 ) (1) Included in direct expenses and unallocated selling, general, and administrative costs are the depreciation and amortization expense amounts below:
Depreciation and Amortization Expense Included in Direct Expenses and Unallocated Selling, General, and Administrative Costs	Depreciation and Amortization Expense Quarter Ended Nine Months Ended 2018 2017 2018 2017 (Thousands of dollars) Segment Direct Expense: Oil and Gas $ 13,175 $ 9,615 $ 36,444 $ 29,301 Air Medical 5,274 4,885 16,989 15,581 Technical Services 128 146 415 440 Total $ 18,577 $ 14,646 $ 53,848 $ 45,322 Unallocated SG&A $ 2,366 $ 1,936 $ 5,693 $ 5,271 (2) Includes equity in (earnings) of unconsolidated affiliates, net. (3) Consists of (gains) losses on disposition of property and equipment and other income. (4) Represents corporate overhead expenses not allocable to segments.

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Balance Sheets	PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS (Thousands of dollars) (Unaudited) September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS Current Assets: Cash $ 9,905 $ 1,880 $ 4,668 $ — $ 16,453 Short-term investments 30,509 — — — 30,509 Accounts receivable – net 75,970 95,340 29,574 (3,477 ) 197,407 Intercompany receivable — 92,338 — (92,338 ) — Inventories of spare parts – net 60,914 10,646 2,792 — 74,352 Prepaid expenses 9,364 2,640 1,197 — 13,201 Income taxes receivable 139 510 — — 649 Total current assets 186,801 203,354 38,231 (95,815 ) 332,571 Investment in subsidiaries 415,980 — — (415,980 ) — Property and equipment – net 598,363 286,015 39,199 — 923,577 Restricted cash and investments 19,781 — — — 19,781 Other assets 140,265 1,042 (131,165 ) — 10,142 Deferred income tax — — 1,009 — 1,009 Goodwill — — 61,299 — 61,299 Intangible assets — — 15,557 — 15,557 Total assets $ 1,361,190 $ 490,411 $ 24,130 $ (511,795 ) $ 1,363,936 LIABILITIES AND SHAREHOLDERS’ EQUITY Current Liabilities: Short-term debt $ 499,429 $ — $ — $ — $ 499,429 Accounts payable 32,458 5,200 5,028 (3,477 ) 39,209 Accrued and other current liabilities 18,781 14,053 6,723 — 39,557 Intercompany payable 81,384 — 10,954 (92,338 ) — Total current liabilities 632,052 19,253 22,705 (95,815 ) 578,195 Long-term debt 129,126 — — — 129,126 Deferred income taxes and other long-term liabilities 18,536 57,439 3,255 — 79,230 Shareholders’ Equity: Common stock and paid-in capital 314,085 77,952 1,510 (79,462 ) 314,085 Accumulated other comprehensive loss (3 ) — (4,091 ) — (4,094 ) Retained earnings 267,394 335,767 751 (336,518 ) 267,394 Total shareholders’ equity 581,476 413,719 (1,830 ) (415,980 ) 577,385 Total liabilities and shareholders’ equity $ 1,361,190 $ 490,411 $ 24,130 $ (511,795 ) $ 1,363,936 PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING BALANCE SHEETS (Thousands of dollars) December 31, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated ASSETS Current Assets: Cash $ 47 $ 1,072 $ 7,651 $ — $ 8,770 Short-term investments 64,237 — — — 64,237 Accounts receivable – net 90,077 74,886 38,020 (17,004 ) 185,979 Intercompany receivable — 126,366 — (126,366 ) — Inventories of spare parts – net 68,737 9,049 3,095 — 80,881 Prepaid expenses 8,348 1,898 1,229 — 11,475 Income taxes receivable 345 9 917 — 1,271 Total current assets 231,791 213,280 50,912 (143,370 ) 352,613 Investment in subsidiaries and others 397,301 — — (397,301 ) — Property and equipment – net 617,488 284,984 44,293 — 946,765 Restricted investments 12,382 — 14 — 12,396 Other assets 139,754 908 (131,921 ) — 8,741 Deferred income tax — — 3,309 — 3,309 Goodwill — — 61,299 — 61,299 Intangible assets — — 16,723 — 16,723 Total assets $ 1,398,716 $ 499,172 $ 44,629 $ (540,671 ) $ 1,401,846 LIABILITIES AND SHAREHOLDERS’ EQUITY Current Liabilities: Accounts payable $ 28,130 $ 4,636 $ 21,425 $ (17,005 ) $ 37,186 Accrued and other current liabilities 23,147 10,577 8,126 — 41,850 Intercompany payable 113,387 — 12,978 (126,365 ) — Total current liabilities 164,664 15,213 42,529 (143,370 ) 79,036 Long-term debt 615,994 — — — 615,994 Deferred income taxes and other long-term liabilities 5,404 84,300 4,458 — 94,162 Shareholders’ Equity: Common stock and paid-in capital 309,933 77,951 1,375 (79,326 ) 309,933 Accumulated other comprehensive loss (280 ) — — — (280 ) Retained earnings 303,001 321,708 (3,733 ) (317,975 ) 303,001 Total shareholders’ equity 612,654 399,659 (2,358 ) (397,301 ) 612,654 Total liabilities and shareholders’ equity $ 1,398,716 $ 499,172 $ 44,629 $ (540,671 ) $ 1,401,846
Condensed Consolidating Statements of Operations	PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) (Unaudited) For the Quarter Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 75,654 $ 72,396 $ 22,027 $ (1,290 ) $ 168,787 Expenses: Direct expenses 83,935 62,045 15,510 (1,290 ) 160,200 Selling, general and administrative expenses 9,987 3,666 2,606 (4 ) 16,255 Total operating expenses 93,922 65,711 18,116 (1,294 ) 176,455 Gain on disposal of assets, net — — — — — Equity in income of unconsolidated affiliates, net (118 ) — — — (118 ) Operating (loss) income (18,150 ) 6,685 3,911 4 (7,550 ) Equity in net income of consolidated subsidiaries (10,381 ) — — 10,381 — Interest expense 8,356 1 — — 8,357 Other income, net (301 ) — (1,548 ) 4 (1,845 ) (2,326 ) 1 (1,548 ) 10,385 6,512 (Loss) earnings before income taxes (15,824 ) 6,684 5,459 (10,381 ) (14,062 ) Income tax (benefit) expense (4,293 ) — 1,762 — (2,531 ) Net (loss) earnings $ (11,531 ) $ 6,684 $ 3,697 $ (10,381 ) $ (11,531 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) For the Quarter Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 79,644 $ 70,692 $ 7,784 $ (7,953 ) $ 150,167 Expenses: Direct expenses 83,727 51,247 9,765 (7,953 ) 136,786 Selling, general and administrative expenses 8,240 3,141 24 (4 ) 11,401 Total operating expenses 91,967 54,388 9,789 (7,957 ) 148,187 Loss (gain) on disposal of assets, net (4 ) — — — (4 ) Equity in (income) loss of consolidated affiliate 112 — (550 ) — (438 ) Operating (loss) income (12,431 ) 16,304 (1,455 ) 4 2,422 Equity in net income of consolidated subsidiaries (14,850 ) — — 14,850 — Interest expense 8,027 — — — 8,027 Other income, net (709 ) (1 ) — 4 (706 ) (7,532 ) (1 ) — 14,854 7,321 (Loss) earnings before income taxes (4,899 ) 16,305 (1,455 ) (14,850 ) (4,899 ) Income tax (benefit) expense (1,622 ) — — — (1,622 ) Net (loss) earnings $ (3,277 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,277 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 233,608 $ 199,823 $ 68,065 $ (3,096 ) $ 498,400 Expenses: Direct expenses 246,888 175,673 52,045 (3,097 ) 471,509 Selling, general and administrative expenses 27,129 10,089 8,994 (13 ) 46,199 Total operating expenses 274,017 185,762 61,039 (3,110 ) 517,708 Loss (gain) on disposal of assets, net 729 — (21 ) — 708 Equity in income of unconsolidated affiliates, net (162 ) — — — (162 ) Operating (loss) income (40,976 ) 14,061 7,047 14 (19,854 ) Equity in net income of consolidated subsidiaries (18,542 ) — — 18,542 — Interest expense 24,888 2 4 — 24,894 Other income, net (359 ) — (91 ) 14 (436 ) 5,987 2 (87 ) 18,556 24,458 (Loss) earnings before income taxes (46,963 ) 14,059 7,134 (18,542 ) (44,312 ) Income tax (benefit) expense (11,356 ) — 2,651 — (8,705 ) Net (loss) earnings $ (35,607 ) $ 14,059 $ 4,483 $ (18,542 ) $ (35,607 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF OPERATIONS (Thousands of dollars) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Operating revenues, net $ 228,973 $ 197,022 $ 15,987 $ (10,773 ) $ 431,209 Expenses: Direct expenses 238,669 155,434 16,920 (10,773 ) 400,250 Selling, general and administrative expenses 29,265 9,296 144 (14 ) 38,691 Total operating expenses 267,934 164,730 17,064 (10,787 ) 438,941 Loss (gain) on disposal of assets, net 4 (1 ) — — 3 Equity in loss of unconsolidated affiliate 1,040 — 516 — 1,556 Operating (loss) income (40,005 ) 32,293 (1,593 ) 14 (9,291 ) Equity in net income of consolidated subsidiaries (32,093 ) — — 32,093 — Interest expense 24,283 22 — — 24,305 Other income, net (2,486 ) (2 ) — 14 (2,474 ) (10,296 ) 20 — 32,107 21,831 (Loss) earnings before income taxes (29,709 ) 32,273 (1,593 ) (32,093 ) (31,122 ) Income tax (benefit) expense (7,911 ) (1,413 ) — — (9,324 ) Net (loss) earnings $ (21,798 ) $ 33,686 $ (1,593 ) $ (32,093 ) $ (21,798 )
Condensed Consolidated Statements of Comprehensive Income (Loss)	PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Quarter Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (11,531 ) $ 6,684 $ 3,697 $ (10,381 ) $ (11,531 ) Unrealized gain on short-term investments — — — — — Currency translation adjustments — — (4,718 ) — (4,718 ) Changes in pension plan asset and benefit obligation — — — — — Tax effect of the above-listed adjustments — — — — — Total comprehensive (loss) income $ (11,531 ) $ 6,684 $ (1,021 ) $ (10,381 ) $ (16,249 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) For the Quarter Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (3,277 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,277 ) Unrealized gain on short-term investments 41 — — — 41 Changes in pension plan asset and benefit obligations (24 ) — — — (24 ) Tax effect of the above-listed adjustments (8 ) — — — (8 ) Total comprehensive (loss) income $ (3,268 ) $ 16,305 $ (1,455 ) $ (14,850 ) $ (3,268 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (35,607 ) $ 14,059 $ 4,483 $ (18,542 ) (35,607 ) Unrealized gain on short-term investments 363 — — — 363 Currency translation adjustment — — (4,091 ) — (4,091 ) Changes in pension plan asset and benefit obligation (1 ) — — — (1 ) Tax effect of the above-listed adjustments (85 ) — — — (85 ) Total comprehensive (loss) income $ (35,330 ) $ 14,059 $ 392 $ (18,542 ) $ (39,421 ) PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net (loss) earnings $ (21,798 ) $ 33,686 $ (1,593 ) $ (32,093 ) (21,798 ) Unrealized gain on short-term investments 370 — — — 370 Changes in pension plan asset and benefit obligations (2 ) — — — (2 ) Tax effect of the above-listed adjustments (134 ) — — — (134 ) Total comprehensive (loss) income $ (21,564 ) $ 33,686 $ (1,593 ) $ (32,093 ) $ (21,564 )
Condensed Consolidating Statements of Cash Flows	PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (Thousands of dollars) (Unaudited) For the Nine Months Ended September 30, 2018 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net cash (used in) provided by operating activities $ (25,451 ) $ 6,439 $ 10,964 $ — $ (8,048 ) Investing activities: Purchase of property and equipment (20,580 ) — (2,181 ) — (22,761 ) Proceeds from asset dispositions 1,453 — — — 1,453 Purchase of short-term investments (284,277 ) — — — (284,277 ) Purchase of restricted investments (7,705 ) — — — (7,705 ) Proceeds from sale of short-term investments 318,007 — — — 318,007 Loan to unconsolidated affiliate (274 ) — — — (274 ) Net cash (used in) investing activities 6,624 — (2,181 ) — 4,443 Financing activities: Debt issuance costs (874 ) — — — (874 ) Proceeds from line of credit 34,295 — — — 34,295 Payments on line of credit (151,795 ) — — — (151,795 ) Proceeds from Term Loan 130,000 130,000 Due to/from affiliate, net 17,158 (5,631 ) (11,527 ) — — Repurchase of common stock (99 ) — — — (99 ) Net cash provided by (used in) financing activities 28,685 (5,631 ) (11,527 ) — 11,527 Effect of exchange rate changes on cash — — (239 ) — (239 ) Increase (decrease) in cash 9,858 808 (2,983 ) — 7,683 Cash, beginning of period 47 1,072 7,651 — 8,770 Cash, end of period $ 9,905 $ 1,880 $ 4,668 $ — $ 16,453 PHI, INC. AND SUBSIDIARIES CONDENSED CONSOLIDATING STATEMENTS OF CASH FLOWS (Thousands of dollars) For the Nine Months Ended September 30, 2017 Parent Guarantor Non-Guarantor Subsidiaries Eliminations Consolidated Net cash (used in) provided by operating activities $ (43,328 ) $ 33,670 $ 7,790 $ — $ (1,868 ) Investing activities: Purchase of property and equipment (49,227 ) — — — (49,227 ) Proceeds from asset dispositions 21 — — — 21 Purchase of short-term investments (268,525 ) — — (268,525 ) Proceeds from sale of short-term investments 354,250 — — 354,250 Payments of deposits on aircraft — — — — Net cash provided by investing activities 36,519 — — — 36,519 Financing activities: Proceeds from line of credit 99,150 — — — 99,150 Payments on line of credit (133,150 ) — — — (133,150 ) Repurchase of common stock (256 ) — — — (256 ) Due to/from affiliate, net 41,079 (34,699 ) (6,380 ) — — Net cash provided by (used in) financing activities 6,823 (34,699 ) (6,380 ) — (34,256 ) Increase (decreased) in cash 14 (1,029 ) 1,410 — 395 Cash, beginning of period 36 2,100 460 — 2,596 Cash, end of period $ 50 $ 1,071 $ 1,870 $ — $ 2,991

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Typical contract length	30 days
Provisional income tax benefit related to remeasurement of deferred tax balances		$ 49.2
Minimum [Member]
Disaggregation of Revenue [Line Items]
Typical contract length	1 year
Accounts receivable invoice term	30 days
Contract termination notice period	30 days
Maximum [Member]
Disaggregation of Revenue [Line Items]
Typical contract length	7 years
Accounts receivable invoice term	60 days
Contract termination notice period	180 days
Oil and Gas [Member]
Disaggregation of Revenue [Line Items]
Receivables	$ 103.1	106.8
Air Medical [Member]
Disaggregation of Revenue [Line Items]
Receivables	91.8	74.4
Technical Services [Member]
Disaggregation of Revenue [Line Items]
Receivables	$ 2.5	$ 4.8

Basis of Presentation - Disaggr

Basis of Presentation - Disaggregated Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Operating revenues, net	$ 168,787	$ 150,167	$ 498,400	$ 431,209
Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	168,787	150,167	498,400	431,209
Oil and Gas [Member] | Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	93,338	75,700	286,046	222,098
Air Medical [Member] | Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	70,192	70,280	194,331	192,840
Technical Services [Member] | Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	5,257	4,187	18,023	16,271
Traditional Provider Model [Member] | Air Medical [Member] | Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	12,414	11,816	36,371	35,427
Independent Provider Model [Member] | Air Medical [Member] | Operating Segments [Member]
Disaggregation of Revenue [Line Items]
Operating revenues, net	$ 57,778	$ 58,464	$ 157,960	$ 157,413

Investments - Components of Inv

Investments - Components of Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Cost Basis	$ 51,142	$ 79,667
Unrealized Gains	0	0
Unrealized Losses	0	(364)
Fair Value	51,142	79,303
Money Market Mutual Funds [Member]
Debt Securities, Available-for-sale [Line Items]
Cost Basis	50,290	5,601
Fair Value	50,290	5,601
US Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Cost Basis		7,501
Unrealized Losses		(34)
Fair Value		7,467
Corporate Bonds and Notes [Member]
Debt Securities, Available-for-sale [Line Items]
Cost Basis		63,880
Unrealized Gains		0
Unrealized Losses		(330)
Fair Value		63,550
Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Cost Basis		76,982
Unrealized Gains		0
Unrealized Losses		(364)
Fair Value		76,618
Deferred Compensation Plan Assets [Member]
Debt Securities, Available-for-sale [Line Items]
Cost Basis	852	2,685
Fair Value	$ 852	$ 2,685

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Restricted investments	$ 19,781	$ 12,396

Investments - Cost and Fair Val

Investments - Cost and Fair Value of Debt Investments Based on Maturities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-sale Securities, Debt Maturities [Abstract]
Due in one year or less, Amortized Costs	$ 0	$ 31,348
Due within two years, Amortized Costs	0	40,032
Total, Cost Basis	0	71,380
Due in one year or less, Fair Value	0	31,254
Due within two years, Fair Value	0	39,763
Total, Fair Value	$ 0	$ 71,017

Investments - Average Coupon Ra

Investments - Average Coupon Rate Percentage and the Average Days to Maturity of Debt (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
US Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Average Coupon Rate	0.00%	1.37%
Average Days To Maturity	0 days	370 days
Corporate Bonds and Notes [Member]
Debt Securities, Available-for-sale [Line Items]
Average Coupon Rate	0.00%	1.766%
Average Days To Maturity	0 days	392 days

Investments - Investments in Co

Investments - Investments in Continuous Unrealized Loss Position for Less Than Twelve Months (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 0	$ 49,541
Unrealized Losses	0	(299)
US Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	5,472
Unrealized Losses	0	(28)
Corporate Bonds and Notes [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	44,069
Unrealized Losses	$ 0	$ (271)

Investments - Investments in _2

Investments - Investments in Continuous Unrealized Loss Position for More Than Twelve Months (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 0	$ 21,476
Unrealized Losses	0	(65)
US Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	1,994
Unrealized Losses	0	(6)
Corporate Bonds and Notes [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	19,482
Unrealized Losses	$ 0	$ (59)

Valuation Accounts - Additional

Valuation Accounts - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for doubtful accounts	$ 6.8		$ 6.8		$ 7.2
Value of services to patients who are unable to pay	2.2	$ 1.3	7.1	$ 5.7
Estimated cost of providing charity services	0.5	$ 0.3	1.7	$ 1.3
Valuation reserves related to obsolescence and slow moving inventory	23.1		23.1		20.9
Air Medical [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for contractual discounts against outstanding accounts receivable	119.9		119.9		117.8
Allowance for uncompensated care against outstanding accounts receivable	$ 64.7		$ 64.7		$ 52.5

Valuation Accounts - Schedule o

Valuation Accounts - Schedule of Allowance for Contractual Discounts and Estimated Uncompensated Care as a Percentage of Gross Segment Accounts Receivable (Detail) - Air Medical [Member] - Trade Accounts Receivable [Member]	Sep. 30, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for Contractual Discounts	48.00%	53.00%
Allowance for Uncompensated Care	26.00%	24.00%

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Valuation of Investments and Financial Instruments Pricing Levels (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 51,142	$ 79,303
Money Market Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	50,290	5,601
US Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		7,467
Corporate Bonds and Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		63,550
Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		76,618
Deferred Compensation Plan Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	852	2,685
(Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	51,142	8,286
(Level 1) [Member] | Money Market Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	50,290	5,601
(Level 1) [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		5,601
(Level 1) [Member] | Deferred Compensation Plan Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	852	2,685
(Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 0	71,017
(Level 2) [Member] | US Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		7,467
(Level 2) [Member] | Corporate Bonds and Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		63,550
(Level 2) [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total		$ 71,017

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Mar. 17, 2014
Fair Value Measurements Disclosure [Line Items]
The fair value investments reclassification of assets between level 1 and level 2	$ 0	$ 0
The fair value of Senior Notes, based on quoted market prices	477,100,000	499,200,000
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements Disclosure [Line Items]
Level 3 investments	$ 0	$ 0
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member]
Fair Value Measurements Disclosure [Line Items]
Interest rate on Senior Notes	5.25%		5.25%

Debt - Components of Long-term

Debt - Components of Long-term Debt (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Principal	$ 630,000	$ 617,500
Unamortized debt issuance debt costs	1,445	1,506
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal	0	117,500
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Principal	500,000	500,000
Unamortized debt issuance debt costs	571	$ 1,506
6% Related Party Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Principal	130,000
Unamortized debt issuance debt costs	$ 874

Debt - Components of Long-ter_2

Debt - Components of Long-term Debt (Additional Information) (Detail) - 5.25% Senior Notes due March 15, 2019 [Member] - Senior Notes [Member]	9 Months Ended
	Sep. 30, 2018	Mar. 17, 2014
Debt Instrument [Line Items]
Interest rate on Senior Notes	5.25%	5.25%
Senior Notes payable periods	Mar. 15, 2019

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Sep. 28, 2018	Sep. 30, 2018	Dec. 31, 2017	Mar. 17, 2014
Debt Instrument [Line Items]
Letters of credit outstanding under the facility		$ 19,800,000	$ 19,600,000
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate on debt		5.25%		5.25%
Maturity date of Senior notes payable		Mar. 15, 2019
Debt instrument interest rate term		Interest is payable semi-annually on March 15 and September 15 of each year.
Debt instrument restrictive covenants		The indenture governing the 2019 Notes (the “2019 Indenture”) contains, among other things, certain restrictive covenants, including limitations on incurring indebtedness, creating liens, selling assets and entering into certain transactions with affiliates. The covenants also limit PHI’s ability to, among other things, pay cash dividends on common stock, repurchase or redeem common or preferred equity, prepay subordinated debt and make certain investments.
Percentage of principal amount redeemed		101.00%
Related party term loan, amount issued				$ 500,000,000
6% Related Party Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Interest rate on debt		6.00%
Related party term loan, amount issued	$ 130,000,000
Proceeds from related party debt	130,000,000
Letter of Credit to Secure workers Compensation Policies, Air Medical License, and a Traditional Provider Contract [Member]
Debt Instrument [Line Items]
Letters of credit outstanding under the facility		$ 12,000,000
Letter of Credit to Guaranty International Contract Performance [Member]
Debt Instrument [Line Items]
Letters of credit outstanding under the facility		$ 7,800,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of senior secured revolving credit facility, including accrued interest	$ 122,700,000

Earnings Per Share - Components

Earnings Per Share - Components of Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average outstanding shares of common stock, basic	15,816	15,799	15,811	15,750
Dilutive effect of unvested restricted stock units	0	0	0	0
Weighted average outstanding shares of common stock, diluted	15,816	15,799	15,811	15,750

Earnings Per Share - Componen_2

Earnings Per Share - Components of Basic and Diluted Earnings Per Share (Additional Information) (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Anti-dilutive securities (in shares)	108	0	0	0

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Share Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock-based compensation expense:
Total stock-based compensation expense	$ 2,118	$ 1,271	$ 4,250	$ 3,074
Time-based Restricted Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	5,001	26,296	326,832	472,913
Stock-based compensation expense:
Total stock-based compensation expense	$ 1,085	$ 582	$ 2,162	$ 1,678
Performance-based Restricted Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0	4,646	448,012	371,045
Stock-based compensation expense:
Total stock-based compensation expense	$ 1,033	$ 689	$ 2,088	$ 1,396

Asset Disposals - Additional In

Asset Disposals - Additional Information (Detail) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2018Aircraft	Jun. 30, 2018Aircraft	Mar. 31, 2018Aircraft	Sep. 30, 2017Aircraft	Jun. 30, 2017Aircraft	Mar. 31, 2017Aircraft	Sep. 30, 2018USD ($)
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold						0
Cash realized from sale of assets | $							$ 1.5
Gain (loss) on disposal of assets | $							$ 0.7
Medium Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold					5
Air Medical [Member] | Light Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold			1
Oil and Gas [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft donated			1
Oil and Gas [Member] | Light Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold		1
Oil and Gas [Member] | Medium Aircraft [Member]
Assets Held For Sale And Impairments [Line Items]
Number of aircraft sold	1	1		1

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)Land_Parcel
Long-term Purchase Commitment [Line Items]
Purchase commitment for aircraft	$ 0
Total aircraft deposits	500,000
Aggregate estimated probable liability environmental matters	$ 150,000
Number of parcels of land exists | Land_Parcel	2
Aggregate commitments under operating leases	$ 173,200,000
Operational lease payable	11,000,000
Lease commitment for aircraft	154,100,000
Facility lease commitments	19,100,000
2019 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	129,000,000
2020 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	$ 22,700,000

Goodwill (Details)

Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Roll Forward]
Goodwill, beginning	$ 61,299
Activity	0
Goodwill, ending	61,299
Oil and Gas [Member]
Goodwill [Roll Forward]
Goodwill, beginning	61,299
Activity	0
Goodwill, ending	61,299
Air Medical [Member]
Goodwill [Roll Forward]
Goodwill, beginning	0
Activity	0
Goodwill, ending	0
Technical Services [Member]
Goodwill [Roll Forward]
Goodwill, beginning	0
Activity	0
Goodwill, ending	$ 0

Other Intangible Assets (Detail

Other Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Amount at December 31, 2017	$ 16,723
Accumulated Amortization	(1,166)
Net Balance at September 30, 2018	$ 15,557	$ 16,723
Customer Relationship [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	15 years
Gross Amount at December 31, 2017	$ 11,622
Accumulated Amortization	(581)
Net Balance at September 30, 2018	$ 11,041
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	5 years
Gross Amount at December 31, 2017	$ 900
Accumulated Amortization	(135)
Net Balance at September 30, 2018	$ 765
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	7 years
Gross Amount at December 31, 2017	$ 4,201
Accumulated Amortization	(450)
Net Balance at September 30, 2018	$ 3,751

Other Intangible Assets - Futur

Other Intangible Assets - Future Amortization of Intangible Assets (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 1.6	$ 1.6
2,019	1.6	1.6
2,020	1.6	1.6
2,021	1.6	1.6
2,022	1.6	1.6
Amortization expense	$ 0.4	$ 1.2

Segment Information - Additiona

Segment Information - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018StatesAircraftLocationSegment	Sep. 30, 2017
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			3
National Science Foundation [Member]
Segment Reporting Information [Line Items]
Number of aircraft assigned			6
Fixed Term Customer Contract [Member]
Segment Reporting Information [Line Items]
Segment revenue (percent)	85.00%	89.00%	87.00%	90.00%
Contracted Customers [Member]
Segment Reporting Information [Line Items]
Segment revenue (percent)			13.00%	10.00%
Hospitals Contracts [Member]
Segment Reporting Information [Line Items]
Segment revenue (percent)	17.00%	15.00%	17.00%	17.00%
Minimum [Member]
Segment Reporting Information [Line Items]
Term of contract			1 year
Maximum [Member]
Segment Reporting Information [Line Items]
Term of contract			7 years
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Number of aircraft available for use			126
Segment revenue (percent)	55.00%	50.00%	57.00%	51.00%
Oil and Gas [Member] | Minimum [Member] | Major Customer [Member]
Segment Reporting Information [Line Items]
Working period with major customers			35 years
Oil and Gas [Member] | Minimum [Member] | ENI Petroleum [Member]
Segment Reporting Information [Line Items]
Working period with major customers			20 years
Air Medical [Member]
Segment Reporting Information [Line Items]
Segment revenue (percent)	42.00%	47.00%	39.00%	45.00%
Number of aircraft assigned			108
Number of states in which company operates aircrafts | States			18
Locations in which company operates Aircrafts | Location			80
Technical Services [Member]
Segment Reporting Information [Line Items]
Segment revenue (percent)	3.00%	3.00%	4.00%	4.00%

Segment Information - Schedule

Segment Information - Schedule of Provisions for Contractual Discounts and Estimated Uncompensated Care as a Percentage of Gross Segment Billings (Detail) - Air Medical [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Provisions For Contractual Discounts And Estimated Uncompensated Care [Line Items]
Provision for contractual discounts	65.00%	65.00%	66.00%	66.00%
Provision for uncompensated care	10.00%	6.00%	8.00%	7.00%

Segment Information - Schedul_2

Segment Information - Schedule of Net Revenue Attributable to Insurance, Medicare, Medicaid, and Self-Pay as Percentage of Net Air Medical Revenues (Detail) - Air Medical [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Self-Pay [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	1.00%	1.00%	1.00%	1.00%
Medicaid [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	9.00%	9.00%	8.00%	9.00%
Medicare [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	20.00%	17.00%	20.00%	18.00%
Insurance [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	70.00%	73.00%	71.00%	72.00%

Segment Information - Schedul_3

Segment Information - Schedule of Financial Information Concerning Reportable Operating Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total operating revenues, net	$ 168,787	$ 150,167	$ 498,400	$ 431,209
Total direct expenses	160,200	136,786	471,509	400,250
Total segment selling, general and administrative expenses	16,255	11,401	46,199	38,691
Total net segment profit	(7,550)	2,422	(19,854)	(9,291)
Interest expense	(8,357)	(8,027)	(24,894)	(24,305)
Loss before income taxes	(14,062)	(4,899)	(44,312)	(31,122)
Reportable Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	168,787	150,167	498,400	431,209
Total direct expenses	160,082	136,348	471,347	401,806
Total segment selling, general and administrative expenses	8,343	4,622	24,795	14,813
Total segment direct and selling, general and administrative expenses	168,425	140,970	496,142	416,619
Total net segment profit	362	9,197	2,258	14,590
Reportable Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	93,338	75,700	286,046	222,098
Total direct expenses	94,832	81,467	285,818	236,878
Total segment selling, general and administrative expenses	4,321	1,148	13,642	4,501
Total net segment profit	(5,815)	(6,915)	(13,414)	(19,281)
Reportable Operating Segments [Member] | Air Medical [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	70,192	70,280	194,331	192,840
Total direct expenses	60,358	51,120	170,966	152,363
Total segment selling, general and administrative expenses	3,666	3,136	10,087	9,280
Total net segment profit	6,168	16,024	13,278	31,197
Reportable Operating Segments [Member] | Technical Services [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	5,257	4,187	18,023	16,271
Total direct expenses	4,892	3,761	14,563	12,565
Total segment selling, general and administrative expenses	356	338	1,066	1,032
Total net segment profit	9	88	2,394	2,674
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other, net	1,845	710	(272)	2,471
Interest expense	(8,357)	(8,027)	(24,894)	(24,305)
Corporate [Member]
Segment Reporting Information [Line Items]
Unallocated selling, general and administrative costs	$ (7,912)	$ (6,779)	$ (21,404)	$ (23,878)

Segment Information - Depreciat

Segment Information - Depreciation and Amortization Expense Included in Direct Expenses and Unallocated Selling, General, and Administrative Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reportable Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 18,577	$ 14,646	$ 53,848	$ 45,322
Reportable Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	13,175	9,615	36,444	29,301
Reportable Operating Segments [Member] | Air Medical [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	5,274	4,885	16,989	15,581
Reportable Operating Segments [Member] | Technical Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	128	146	415	440
Corporate [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 2,366	$ 1,936	$ 5,693	$ 5,271

Investment in Variable Intere_2

Investment in Variable Interest Entity and Other Investments and Affiliates - Additional Information (Detail) - PHI Century Limited [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Variable Interest Entity [Line Items]
Investment in the common stock			49.00%	49.00%
PHIC's date of incorporation			May 26, 2011
Earnings (loss) in equity of unconsolidated affiliate	$ (0.1)	$ (0.1)	$ 0.2	$ 1
Trade receivables	4.4		4.4		$ 4
Other assets	0.5		0.5		$ 0.3
Accounts Receivable - Other [Member]
Variable Interest Entity [Line Items]
Loan to affiliate	$ 0.4		$ 0.4

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Mar. 17, 2014
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member]
Supplemental Guarantor Financial Information [Line Items]
Senior notes, amount issued		$ 500,000,000
Interest rate on Senior Notes	5.25%	5.25%
Domestic Subsidiaries [Member]
Supplemental Guarantor Financial Information [Line Items]
Ownership percentage in domestic subsidiaries	100.00%

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Current Assets:
Cash	$ 16,453	$ 8,770	$ 2,991	$ 2,596
Short-term investments	30,509	64,237
Accounts receivable - net	197,407	185,979
Inventories of spare parts – net	74,352	80,881
Prepaid expenses	13,201	11,475
Income taxes receivable	649	1,271
Total current assets	332,571	352,613
Investment in subsidiaries and others		0
Property and equipment – net	923,577	946,765
Restricted investments	19,781	12,396
Other assets	10,142	8,741
Deferred income taxes	1,009	3,309
Goodwill	61,299	61,299
Intangibles	15,557	16,723
Total assets	1,363,936	1,401,846
Current Liabilities:
Short-term debt	499,429
Accounts payable	39,209	37,186
Accrued and other current liabilities	39,557	41,850
Total current liabilities	578,195	79,036
Long-term debt	129,126	615,994
Deferred income taxes and other long-term liabilities	79,230	94,162
Shareholders’ Equity:
Common stock and paid-in capital	314,085	309,933
Accumulated other comprehensive income (loss)	(4,094)	(280)
Retained earnings	267,394	303,001
Total shareholders’ equity	577,385	612,654	582,061	599,778
Total liabilities and shareholders’ equity	1,363,936	1,401,846
Eliminations [Member]
Current Assets:
Accounts receivable - net	(3,477)	(17,004)
Intercompany receivable	(92,338)	(126,366)
Total current assets	(95,815)	(143,370)
Investment in subsidiaries and others	(415,980)	(397,301)
Total assets	(511,795)	(540,671)
Current Liabilities:
Short-term debt	0
Accounts payable	(3,477)	(17,005)
Accrued and other current liabilities		0
Intercompany payable	(92,338)	(126,365)
Total current liabilities	(95,815)	(143,370)
Shareholders’ Equity:
Common stock and paid-in capital	(79,462)	(79,326)
Retained earnings	(336,518)	(317,975)
Total shareholders’ equity	(415,980)	(397,301)
Total liabilities and shareholders’ equity	(511,795)	(540,671)
Parent Company Only (issuer) [Member]
Current Assets:
Cash	9,905	47	50	36
Short-term investments	30,509	64,237
Accounts receivable - net	75,970	90,077
Inventories of spare parts – net	60,914	68,737
Prepaid expenses	9,364	8,348
Income taxes receivable	139	345
Total current assets	186,801	231,791
Investment in subsidiaries and others	415,980	397,301
Property and equipment – net	598,363	617,488
Restricted investments	19,781	12,382
Other assets	140,265	139,754
Total assets	1,361,190	1,398,716
Current Liabilities:
Short-term debt	499,429
Accounts payable	32,458	28,130
Accrued and other current liabilities	18,781	23,147
Intercompany payable	81,384	113,387
Total current liabilities	632,052	164,664
Long-term debt	129,126	615,994
Deferred income taxes and other long-term liabilities	18,536	5,404
Shareholders’ Equity:
Common stock and paid-in capital	314,085	309,933
Accumulated other comprehensive income (loss)	(3)	(280)
Retained earnings	267,394	303,001
Total shareholders’ equity	581,476	612,654
Total liabilities and shareholders’ equity	1,361,190	1,398,716
Guarantor Subsidiaries [Member]
Current Assets:
Cash	1,880	1,072	1,071	2,100
Accounts receivable - net	95,340	74,886
Intercompany receivable	92,338	126,366
Inventories of spare parts – net	10,646	9,049
Prepaid expenses	2,640	1,898
Income taxes receivable	510	9
Total current assets	203,354	213,280
Property and equipment – net	286,015	284,984
Other assets	1,042	908
Total assets	490,411	499,172
Current Liabilities:
Short-term debt	0
Accounts payable	5,200	4,636
Accrued and other current liabilities	14,053	10,577
Total current liabilities	19,253	15,213
Deferred income taxes and other long-term liabilities	57,439	84,300
Shareholders’ Equity:
Common stock and paid-in capital	77,952	77,951
Retained earnings	335,767	321,708
Total shareholders’ equity	413,719	399,659
Total liabilities and shareholders’ equity	490,411	499,172
Non-Guarantor Subsidiaries [Member]
Current Assets:
Cash	4,668	7,651	$ 1,870	$ 460
Accounts receivable - net	29,574	38,020
Inventories of spare parts – net	2,792	3,095
Prepaid expenses	1,197	1,229
Income taxes receivable	0	917
Total current assets	38,231	50,912
Property and equipment – net	39,199	44,293
Restricted investments	0	14
Other assets	(131,165)	(131,921)
Deferred income taxes	1,009	3,309
Goodwill	61,299	61,299
Intangibles	15,557	16,723
Total assets	24,130	44,629
Current Liabilities:
Short-term debt	0
Accounts payable	5,028	21,425
Accrued and other current liabilities	6,723	8,126
Intercompany payable	10,954	12,978
Total current liabilities	22,705	42,529
Deferred income taxes and other long-term liabilities	3,255	4,458
Shareholders’ Equity:
Common stock and paid-in capital	1,510	1,375
Accumulated other comprehensive income (loss)	(4,091)
Retained earnings	751	(3,733)
Total shareholders’ equity	(1,830)	(2,358)
Total liabilities and shareholders’ equity	$ 24,130	$ 44,629

Condensed Consolidating Finan_5

Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	$ 168,787	$ 150,167	$ 498,400	$ 431,209
Expenses:
Direct expenses	160,200	136,786	471,509	400,250
Selling, general and administrative expenses	16,255	11,401	46,199	38,691
Total operating expenses	176,455	148,187	517,708	438,941
(Gain) loss on disposal of assets	0	(4)	708	3
Equity in loss of unconsolidated affiliate, net	(118)	(438)	(162)	1,556
Operating (loss) income	(7,550)	2,422	(19,854)	(9,291)
Interest expense	8,357	8,027	24,894	24,305
Other income, net	(1,845)	(706)	(436)	(2,474)
Total expenses	6,512	7,321	24,458	21,831
(Loss) earnings before income taxes	(14,062)	(4,899)	(44,312)	(31,122)
Income tax benefit	(2,531)	(1,622)	(8,705)	(9,324)
Net loss	(11,531)	(3,277)	(35,607)	(21,798)
Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	(1,290)	(7,953)	(3,096)	(10,773)
Expenses:
Direct expenses	(1,290)	(7,953)	(3,097)	(10,773)
Selling, general and administrative expenses	(4)	(4)	(13)	(14)
Total operating expenses	(1,294)	(7,957)	(3,110)	(10,787)
Operating (loss) income	4	4	14	14
Equity in net income of consolidated subsidiaries	10,381	14,850	18,542	32,093
Interest expense	0		0	0
Other income, net	4	4	14	14
Total expenses	10,385	14,854	18,556	32,107
(Loss) earnings before income taxes	(10,381)	(14,850)	(18,542)	(32,093)
Net loss	(10,381)	(14,850)	(18,542)	(32,093)
Parent Company Only (issuer) [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	75,654	79,644	233,608	228,973
Expenses:
Direct expenses	83,935	83,727	246,888	238,669
Selling, general and administrative expenses	9,987	8,240	27,129	29,265
Total operating expenses	93,922	91,967	274,017	267,934
(Gain) loss on disposal of assets	0	(4)	729	4
Equity in loss of unconsolidated affiliate, net	(118)	112	(162)	1,040
Operating (loss) income	(18,150)	(12,431)	(40,976)	(40,005)
Equity in net income of consolidated subsidiaries	(10,381)	(14,850)	(18,542)	(32,093)
Interest expense	8,356	8,027	24,888	24,283
Other income, net	(301)	(709)	(359)	(2,486)
Total expenses	(2,326)	(7,532)	5,987	(10,296)
(Loss) earnings before income taxes	(15,824)	(4,899)	(46,963)	(29,709)
Income tax benefit	(4,293)	(1,622)	(11,356)	(7,911)
Net loss	(11,531)	(3,277)	(35,607)	(21,798)
Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	72,396	70,692	199,823	197,022
Expenses:
Direct expenses	62,045	51,247	175,673	155,434
Selling, general and administrative expenses	3,666	3,141	10,089	9,296
Total operating expenses	65,711	54,388	185,762	164,730
(Gain) loss on disposal of assets		0		(1)
Operating (loss) income	6,685	16,304	14,061	32,293
Interest expense	1	0	2	22
Other income, net		(1)		(2)
Total expenses	1	(1)	2	20
(Loss) earnings before income taxes	6,684	16,305	14,059	32,273
Income tax benefit		0		(1,413)
Net loss	6,684	16,305	14,059	33,686
Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Operating revenues, net	22,027	7,784	68,065	15,987
Expenses:
Direct expenses	15,510	9,765	52,045	16,920
Selling, general and administrative expenses	2,606	24	8,994	144
Total operating expenses	18,116	9,789	61,039	17,064
(Gain) loss on disposal of assets	0		(21)	0
Equity in loss of unconsolidated affiliate, net		(550)		516
Operating (loss) income	3,911	(1,455)	7,047	(1,593)
Interest expense	0		4	0
Other income, net	(1,548)		(91)	0
Total expenses	(1,548)		(87)	0
(Loss) earnings before income taxes	5,459	(1,455)	7,134	(1,593)
Income tax benefit	1,762		2,651	0
Net loss	$ 3,697	$ (1,455)	$ 4,483	$ (1,593)

Condensed Consolidating Finan_6

Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidated Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net loss	$ (11,531)	$ (3,277)	$ (35,607)	$ (21,798)
Unrealized gain (loss) on short-term investments	0	41	363	370
Currency translation adjustments	(4,718)	0	(4,091)	0
Changes in pension plan asset and benefit obligation	0	(24)	(1)	(2)
Tax effect of the above-listed adjustments	0	(8)	(85)	(134)
Total comprehensive (loss) income	(16,249)	(3,268)	(39,421)	(21,564)
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net loss	(10,381)	(14,850)	(18,542)	(32,093)
Total comprehensive (loss) income	(10,381)	(14,850)	(18,542)	(32,093)
Parent Company Only (issuer) [Member]
Condensed Financial Statements, Captions [Line Items]
Net loss	(11,531)	(3,277)	(35,607)	(21,798)
Unrealized gain (loss) on short-term investments	0	41	363	370
Currency translation adjustments	0		0
Changes in pension plan asset and benefit obligation	0	(24)	(1)	(2)
Tax effect of the above-listed adjustments	0	(8)	(85)	(134)
Total comprehensive (loss) income	(11,531)	(3,268)	(35,330)	(21,564)
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net loss	6,684	16,305	14,059	33,686
Total comprehensive (loss) income	6,684	16,305	14,059	33,686
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net loss	3,697	(1,455)	4,483	(1,593)
Currency translation adjustments	(4,718)		(4,091)
Total comprehensive (loss) income	$ (1,021)	$ (1,455)	$ 392	$ (1,593)

Condensed Consolidating Finan_7

Condensed Consolidating Financial Information - Guarantor Subsidiaries - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ (8,048)	$ (1,868)
Investing activities:
Purchase of property and equipment	(22,761)	(49,227)
Proceeds from asset dispositions	1,453	21
Purchase of short-term investments	(284,277)	(268,525)
Purchase of restricted investments	(7,705)	0
Proceeds from sale of short-term investments	318,007	354,250
Payments of deposits on aircraft		0
Loan to unconsolidated affiliate	(274)	0
Net cash (used in) investing activities	4,443	36,519
Financing activities:
Debt issuance cost	(874)	0
Proceeds from line of credit	34,295	99,150
Payments on line of credit	(151,795)	(133,150)
Proceeds from Term Loan	130,000	0
Repurchase of common stock	(99)	(256)
Net cash provided by (used in) financing activities	11,527	(34,256)
Effect of exchange rate changes on cash	(239)	0
Increase (decrease) in cash	7,683	395
Cash, beginning of period	8,770	2,596
Cash, end of period	16,453	2,991
Parent Company Only (issuer) [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(25,451)	(43,328)
Investing activities:
Purchase of property and equipment	(20,580)	(49,227)
Proceeds from asset dispositions	1,453	21
Purchase of short-term investments	(284,277)	(268,525)
Purchase of restricted investments	(7,705)
Proceeds from sale of short-term investments	318,007	354,250
Payments of deposits on aircraft		0
Loan to unconsolidated affiliate	(274)
Net cash (used in) investing activities	6,624	36,519
Financing activities:
Debt issuance cost	(874)
Proceeds from line of credit	34,295	99,150
Payments on line of credit	(151,795)	(133,150)
Proceeds from Term Loan	130,000
Repurchase of common stock	(99)	(256)
Due to/from affiliate, net	17,158	41,079
Net cash provided by (used in) financing activities	28,685	6,823
Effect of exchange rate changes on cash	0
Increase (decrease) in cash	9,858	14
Cash, beginning of period	47	36
Cash, end of period	9,905	50
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	6,439	33,670
Investing activities:
Purchase of property and equipment		0
Net cash (used in) investing activities	0	0
Financing activities:
Due to/from affiliate, net	(5,631)	(34,699)
Net cash provided by (used in) financing activities	(5,631)	(34,699)
Effect of exchange rate changes on cash	0
Increase (decrease) in cash	808	(1,029)
Cash, beginning of period	1,072	2,100
Cash, end of period	1,880	1,071
Non-Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	10,964	7,790
Investing activities:
Purchase of property and equipment	(2,181)	0
Net cash (used in) investing activities	(2,181)	0
Financing activities:
Due to/from affiliate, net	(11,527)	(6,380)
Net cash provided by (used in) financing activities	(11,527)	(6,380)
Effect of exchange rate changes on cash	(239)
Increase (decrease) in cash	(2,983)	1,410
Cash, beginning of period	7,651	460
Cash, end of period	$ 4,668	$ 1,870