Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements - Effective January 1, 2017, we adopted ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The new standard requires that excess tax benefits and deficiencies resulting from stock-based compensation awards vesting and exercises be recognized in the income statement. Previously, these amounts were recognized in additional paid-in capital. As a result, during the first quarter of 2017 we recorded a cumulative-effect adjustment of $1.0 million increasing retained earnings and decreasing deferred tax liability on our balance sheet dated March 31, 2017. Accordingly, we recorded income tax expense of $0.5 million in our consolidated statement of income for the three months ended March 31, 2017, in recognition of excess tax deficiencies related to equity compensation. Under this new standard, the corresponding cash flows are now reflected in cash provided by operating activities instead of financing activities, as was previously required. ASU 2016-09 also allows an employer with a statutory income tax withholding obligation to withhold shares with a fair value up to the amount of tax owed using the maximum statutory tax rate in the employee’s applicable jurisdiction. We have elected to continue to withhold the minimum statutory withholding obligation for outstanding awards. We have also elected to continue to estimate equity award forfeitures expected to occur to determine the amount of compensation cost to be recognized in each period New Accounting Pronouncements - In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers, which provides a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. Entities can transition to the standard either retrospectively or as a cumulative effect adjustment as of the date of adoption. The standard is effective for us beginning January 1, 2018, with early adoption permitted as of January 1, 2017. Revenues from our Oil and Gas segment and Air Medical segment hospital contracts are primarily comprised of a fixed monthly fee for a particular model of aircraft, plus a variable component based on flight time. Under the independent provider programs of our Air Medical segment, our revenues are based on a flat rate plus a variable charge per patient-loaded mile, and are recorded net of contractual allowances. We also generate revenue on a cost-plus basis in our Technical Services segment. We are continuing to assess the effects of this standard on each revenue stream of our business and the overall effect on our financial position, results of operations and cash flows and have not yet selected a method of adoption. We intend to adopt the standard beginning January 1, 2018. 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 plan to adopt this standard no later than January 1, 2019. We are currently evaluating the effects of this standard, and expect the adoption of this standard will result in a material change to our consolidated assets and liabilities based on our lease portfolio as of December 31, 2016. 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. The effects of this standard on our financial position, results of operations, and cash flows are not yet known. 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. Early adoption is permitted. The effects of this standard on our financial position, results of operations, and cash flows are not yet known. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. ASU 2017-04 simplifies the current two-step goodwill impairment test by eliminating Step 2 of the test. The new standard requires a one-stepimpairment test in which an entity compares the fair value of a reporting unit with its carrying amount and recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, if any. This standard is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, and should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We do not expect this ASU to have a material impact on our consolidated financial statements.

Recently Adopted Accounting Pronouncements - Effective January 1, 2017, we adopted ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The new standard requires that excess tax benefits and deficiencies resulting from stock-based compensation awards vesting and exercises be recognized in the income statement. Previously, these amounts were recognized in additional paid-in capital. As a result, during the first quarter of 2017 we recorded a cumulative-effect adjustment of $1.0 million increasing retained earnings and decreasing deferred tax liability on our balance sheet dated March 31, 2017. Accordingly, we recorded income tax expense of $0.5 million in our consolidated statement of income for the three months ended March 31, 2017, in recognition of excess tax deficiencies related to equity compensation. Under this new standard, the corresponding cash flows are now reflected in cash provided by operating activities instead of financing activities, as was previously required.

ASU 2016-09 also allows an employer with a statutory income tax withholding obligation to withhold shares with a fair value up to the amount of tax owed using the maximum statutory tax rate in the employee’s applicable jurisdiction. We have elected to continue to withhold the minimum statutory withholding obligation for outstanding awards. We have also elected to continue to estimate equity award forfeitures expected to occur to determine the amount of compensation cost to be recognized in each period

New Accounting Pronouncements - In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers, which provides a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. Entities can transition to the standard either retrospectively or as a cumulative effect adjustment as of the date of adoption. The standard is effective for us beginning January 1, 2018, with early adoption permitted as of January 1, 2017. Revenues from our Oil and Gas segment and Air Medical segment hospital contracts are primarily comprised of a fixed monthly fee for a particular model of aircraft, plus a variable component based on flight time. Under the independent provider programs of our Air Medical segment, our revenues are based on a flat rate plus a variable charge per patient-loaded mile, and are recorded net of contractual allowances. We also generate revenue on a cost-plus basis in our Technical Services segment. We are continuing to assess the effects of this standard on each revenue stream of our business and the overall effect on our financial position, results of operations and cash flows and have not yet selected a method of adoption. We intend to adopt the standard beginning January 1, 2018.

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 plan to adopt this standard no later than January 1, 2019. We are currently evaluating the effects of this standard, and expect the adoption of this standard will result in a material change to our consolidated assets and liabilities based on our lease portfolio as of December 31, 2016.

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. The effects of this standard on our financial position, results of operations, and cash flows are not yet known.

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. Early adoption is permitted. The effects of this standard on our financial position, results of operations, and cash flows are not yet known.

In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. ASU 2017-04 simplifies the current two-step goodwill impairment test by eliminating Step 2 of the test. The new standard requires a one-stepimpairment test in which an entity compares the fair value of a reporting unit with its carrying amount and recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, if any. This standard is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, and should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We do not expect this ASU to have a material impact on our consolidated financial statements.