Macquarie Infrastructure 10-K 21 Feb 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016	Dec. 31, 2015	May 21, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Registrant Name	Macquarie Infrastructure Corp
Entity Central Index Key	1,289,790
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 5,497,965,173
Trading Symbol	MIC
Entity Common Stock, Shares Outstanding		82,125,367
Common stock, par value per share	$ 0.001	$ 0.001		$ 0.001	$ 0.001

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	[1]
Current assets:
Cash and cash equivalents		$ 44,767	$ 22,394
Restricted cash		16,420	18,946
Accounts receivable, less allowance for doubtful accounts of $1,434 and $1,690, respectively		124,846	95,597
Inventories		31,461	29,489
Prepaid expenses		14,561	21,690
Fair value of derivative instruments	[2]	5,514	0
Other current assets		7,099	28,453
Total current assets		244,668	216,569
Property, equipment, land and leasehold improvements, net		4,346,536	4,116,163
Investment in unconsolidated business		8,835	8,274
Goodwill		2,024,409	2,017,211
Intangible assets, net		888,971	934,892
Fair value of derivative instruments	[2]	30,781	1,810
Other noncurrent assets		15,053	13,885
Total assets		7,559,253	7,308,804
Current liabilities:
Due to Manager - related party		6,594	73,317
Accounts payable		69,566	56,688
Accrued expenses		83,734	78,527
Current portion of long-term debt		40,016	40,099
Fair value of derivative instruments	[2]	9,297	19,628
Other current liabilities		41,802	40,531
Total current liabilities		251,009	308,790
Long-term debt, net of current portion		3,039,966	2,746,525
Deferred income taxes		896,116	816,836
Fair value of derivative instruments	[2]	5,966	15,698
Tolling agreements - noncurrent		60,373	68,150
Other noncurrent liabilities		158,289	150,363
Total liabilities		4,411,719	4,106,362
Commitments and contingencies
Stockholders' equity:
Common stock ($0.001 par value; 500,000,000 authorized; 82,047,526 shares issued and outstanding at December 31, 2016 and 80,006,744 shares issued and outstanding at December 31, 2015)	[3]	82	80
Additional paid in capital		2,089,407	2,317,421
Accumulated other comprehensive loss		(28,960)	(23,295)
Retained earnings		892,365	735,984
Total stockholders’ equity		2,952,894	3,030,190
Noncontrolling interests		194,640	172,252
Total equity		3,147,534	3,202,442
Total liabilities and equity		$ 7,559,253	$ 7,308,804
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	Fair value measurements at reporting date were made using significant other observable inputs (level 2).
[3]	See Note 9, “Stockholders’ Equity”, for discussions on preferred stock and special stock.

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable, allowance for doubtful accounts	$ 1,434	$ 1,690
Common stock, par value per share	$ 0.001	$ 0.001
Shares, authorized	500,000,000	500,000,000
Shares, issued	82,047,526	80,006,744
Shares, outstanding	82,047,526	80,006,744

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Service revenue		$ 1,288,562	$ 1,288,501	$ 1,064,682
Product revenue		363,169	350,749	284,400
Financing and equipment lease income		0	0	1,836
Total revenues		1,651,731	1,639,250	1,350,918
Costs and expenses
Cost of services		524,423	551,029	546,609
Cost of product sales		142,731	168,954	192,881
Selling, general and administrative		303,033	304,862	265,254
Fees to Manager - related party		68,486	354,959	168,182
Depreciation		226,492	215,243	98,442
Amortization of intangibles		65,425	101,435	42,695
Total operating expenses		1,330,590	1,696,482	1,314,063
Operating income (loss)		321,141	(57,232)	36,855
Other income (expense)
Interest income		132	55	112
Interest expense	[1]	(116,933)	(123,079)	(73,196)
Equity in earnings and amortization charges of investee		0	0	26,391
Gain from acquisition/divestiture of businesses	[2]	0	0	1,027,054
Other income (expense), net		21,786	1,288	(2,307)
Net income (loss) before income taxes		226,126	(178,968)	1,014,909
(Provision) benefit for income taxes	[3]	(71,257)	65,161	24,374
Net income (loss)		154,869	(113,807)	1,039,283
Less: net loss attributable to noncontrolling interests		(1,512)	(5,270)	(2,745)
Net income (loss) attributable to MIC		$ 156,381	$ (108,537)	$ 1,042,028
Basic income (loss) per share attributable to MIC		$ 1.93	$ (1.39)	$ 16.54
Weighted average number of shares outstanding: basic		80,892,654	77,997,826	62,990,312
Diluted income (loss) per share attributable to MIC		$ 1.85	$ (1.39)	$ 16.1
Weighted average number of shares outstanding: diluted		82,218,627	77,997,826	64,925,565
Cash dividends declared per share		$ 5.05	$ 4.46	$ 3.8875
[1]	Interest expense included losses on derivative instruments of $5.0 million, $28.5 million and $19.5 million for the years ended December 31, 2016, 2015 and 2014, respectively, of which net loss of $856,000 was reclassified from accumulated other comprehensive loss for the year ended December 31, 2014.
[2]	Included the gain of $948.1 million from the acquisition of the remaining 50% interest in IMTT (IMTT Acquisition) from the remeasuring to fair value of the Company’s previous 50% ownership interest and the gain of $78.9 million from the sale of the Company’s interest in the district energy business.
[3]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.

CONSOLIDATED STATEMENTS OF OPE5

CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss in accumulated other comprehensive income reclassifications for cash flow hedges			$ (856)
Reclassification of realized losses of derivatives into earnings, taxes			340
Interest Expense [Member]
Losses on derivative instruments	$ (5,000)	$ (28,500)	(19,500)
District Energy [Member]
Gain on disposal of business			78,900
IMTT [Member]
Fair value gain on previously held interest in equity method investee recognised on business acquisition			$ 948,100

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE [INCOME (LOSS)] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income (loss)		$ 154,869	$ (113,807)	$ 1,039,283
Other comprehensive income (loss), net of taxes:
Reclassification of realized losses of derivatives into earnings	[1]	0	0	636
Change in post-retirement benefit plans	[2]	(2,017)	4,049	(10,816)
Translation adjustment	[3],[4]	2,375	(9,671)	(4,813)
Other comprehensive income (loss)		358	(5,622)	(14,993)
Comprehensive income (loss)		155,227	(119,429)	1,024,290
Less: comprehensive loss attributable to noncontrolling interests	[3]	(78)	(9,147)	(4,633)
Comprehensive income (loss) attributable to MIC		$ 155,305	$ (110,282)	$ 1,028,923
[1]	Reclassification of realized losses of derivatives is composed of (i) pre-tax derivative losses into interest expense of $856,000 and the related tax benefit of $340,000 in the consolidated statements of operations; and (ii) pre-tax derivative losses of $185,000 as an adjustment to investment in unconsolidated business and an adjustment to deferred taxes of $65,000, in the consolidated balance sheet for the year ended December 31, 2014. See Note 9, “Stockholders’ Equity”, for further discussions.
[2]	Change in post-retirement benefit plans is presented net of tax benefit of $1.4 million, tax expense of $2.7 million and tax benefit of $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively. See Note 9, “Stockholders’ Equity”, for further discussions.
[3]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss. See Note 9, “Stockholders’ Equity”, for disclosures on accumulated other comprehensive loss.
[4]	Translation adjustment is presented net of tax expense of $618,000 and tax benefits of $3.9 million and $2.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. See Note 9, “Stockholders’ Equity”, for further discussions.

CONSOLIDATED STATEMENTS OF COM7

CONSOLIDATED STATEMENTS OF COMPREHENSIVE [INCOME (LOSS)] (Parenthetical) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 16, 2014	Jul. 15, 2014
Net loss in accumulated other comprehensive income reclassifications for cash flow hedges					$ (856)
Reclassification of realized losses of derivatives into earnings, taxes					340
Loss in accumulated other comprehensive income reclassifications for cash flow hedges from unconsolidated business					(185)
Reclassification of realized losses of derivatives into earnings from unconsolidated business, taxes					65
Change in post-retirement benefit plans, taxes			1,400	(2,700)	6,900
Translation adjustment, taxes			(618)	$ 3,900	2,700
Equity interest acquired						50.00%
Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member]
Purchase of noncontrolling interest in Subsidiary	[1]		$ (4,589)
IMTT [Member]
Loss in accumulated other comprehensive income reclassifications for cash flow hedges from unconsolidated business					(162)
Reclassification of realized losses of derivatives into earnings from unconsolidated business, taxes					57
Change in post-retirement benefit plans, taxes					(2,300)
Translation adjustment, taxes					$ 23
Equity interest acquired							50.00%
IMTT [Member] | Quebec Marine Terminal [Member]
Equity interest acquired		33.30%
IMTT [Member] | Quebec Marine Terminal [Member] | Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member]
Purchase of noncontrolling interest in Subsidiary		$ (4,600)
[1]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss.

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total		LLC Interest [Member]		LLC Interest [Member]Manager [Member]	[1]	LLC Interest [Member]IMTT Acquisition [Member]		LLC Interest [Member]Independent Directors [Member]	[1]	Common Stock [Member]		Common Stock [Member]Manager [Member]	[2]	Common Stock [Member]Independent Directors [Member]	Additional Paid in Capital [Member]	Additional Paid in Capital [Member]Manager [Member]	Additional Paid in Capital [Member]Independent Directors [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit /Retained Earnings [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2013				$ 1,226,733	[1]							$ 0					$ 21,447			$ (8,445)	$ (197,507)	$ 111,040
Balance (in shares) at Dec. 31, 2013				56,295,595	[1]							0
Issuance of shares				$ 739,452	[1]	$ 101,345				$ 750		$ 0		$ 0		$ 0	0	$ 0	$ 0
Issuance of shares (in shares)				11,504,844	[1]	1,546,918				12,910		0		0		0
Dividends to shareholders	[3]			$ (240,535)													0
Conversion of LLC interests to common stock	[1]			$ 0								$ 0					0
Conversion of LLC interests to common stock (shares)				0								0	[1]
Distributions to noncontrolling interests																						(62,703)
Net adjustment to noncontrolling interest from acquisitions/disposition	[4]																					139,301
Contributions from noncontrolling interests		$ 0																				0
Issuance of shares pursuant to IMTT acquisition		115,000						$ 115,000	[1]
Issuance of shares pursuant to IMTT acquisition (in shares)	[1]							1,729,323
Net income (loss)		1,039,283																			1,042,028	(2,745)
Issuance of shares pursuant to conversion of convertible senior notes		0		$ 0	[1]							$ 0					0
Issuance of shares pursuant to conversion of convertible senior notes (in shares)				0	[1]							0
Purchase of noncontrolling interest	[4]																0			0
Equity component of Convertible senior notes issued in Oct 2016	[5]																0
Other comprehensive income (loss)		(14,993)																		(13,105)		(1,888)
Balance at Dec. 31, 2014		2,970,168		$ 1,942,745	[1]							$ 0					21,447			(21,550)	844,521	183,005
Balance (in shares) at Dec. 31, 2014				71,089,590	[1]							0
Total Stockholders' Equity		2,787,163
Issuance of shares				$ 471,627	[1]	$ 176,256				$ 750		$ 0		$ 1		$ 0	3,822	42,388	0
Issuance of shares (in shares)				6,111,253	[1]	2,213,666				12,525		53,798		525,598		0
Dividends to shareholders	[3]			$ (162,967)													(178,593)
Conversion of LLC interests to common stock	[1]			$ (2,428,413)								$ 79					2,428,334
Conversion of LLC interests to common stock (shares)	[1]			(79,427,057)								79,427,057
Distributions to noncontrolling interests																						(2,138)
Net adjustment to noncontrolling interest from acquisitions/disposition	[4]																					0
Contributions from noncontrolling interests		532																				532
Issuance of shares pursuant to IMTT acquisition		0						$ 0	[1]
Issuance of shares pursuant to IMTT acquisition (in shares)	[1]							0
Net income (loss)		(113,807)																			(108,537)	(5,270)
Issuance of shares pursuant to conversion of convertible senior notes		25		$ 2	[1]							$ 0					23
Issuance of shares pursuant to conversion of convertible senior notes (in shares)				23	[1]							291
Purchase of noncontrolling interest	[4]																0			0
Equity component of Convertible senior notes issued in Oct 2016	[5]																0
Other comprehensive income (loss)		(5,622)																		(1,745)		(3,877)
Balance at Dec. 31, 2015		3,202,442	[6]	$ 0	[1]							$ 80					2,317,421			(23,295)	735,984	172,252
Balance (in shares) at Dec. 31, 2015				0	[1]							80,006,744
Total Stockholders' Equity	[6]	3,030,190
Issuance of shares				$ 0	[1]	$ 0				$ 0		$ 0		$ 2		$ 0	11,751	$ 135,343	$ 750
Issuance of shares (in shares)				0	[1]	0				0		157,649		1,874,426		8,660
Dividends to shareholders	[3]			$ 0													(396,093)
Conversion of LLC interests to common stock	[1]			$ 0								$ 0					0
Conversion of LLC interests to common stock (shares)	[1]			0								0
Distributions to noncontrolling interests																						(4,639)
Net adjustment to noncontrolling interest from acquisitions/disposition	[4]																					11,674
Contributions from noncontrolling interests		15,431																				15,431
Issuance of shares pursuant to IMTT acquisition		0						$ 0	[1]
Issuance of shares pursuant to IMTT acquisition (in shares)	[1]							0
Net income (loss)		154,869																			156,381	(1,512)
Issuance of shares pursuant to conversion of convertible senior notes		4		$ 0	[1]							$ 0					4
Issuance of shares pursuant to conversion of convertible senior notes (in shares)				0	[1]							47
Purchase of noncontrolling interest	[4]																6,102			(4,589)
Equity component of Convertible senior notes issued in Oct 2016	[5]																14,129
Other comprehensive income (loss)		358																		(1,076)		1,434
Balance at Dec. 31, 2016		3,147,534		$ 0	[1]							$ 82					$ 2,089,407			$ (28,960)	$ 892,365	$ 194,640
Balance (in shares) at Dec. 31, 2016				0	[1]							82,047,526
Total Stockholders' Equity		$ 2,952,894
[1]	See Note 9, “Stockholders’ Equity”, for discussion on LLC interests, common stock and additional paid in capital.
[2]	Excludes 100 shares of special stock issued to Manager for the years ended December 31, 2016 and 2015. See Note 9, “Stockholders’ Equity” for further discussion.
[3]	See Note 9, “Stockholders’ Equity”, for discussion on cash dividends paid on shares for each period.
[4]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss. See Note 9, “Stockholders’ Equity”, for disclosures on accumulated other comprehensive loss.
[5]	Represents the stockholders’ equity component of the $402.5 million convertible senior notes issued in October 2016 recorded net of taxes of $11.9 million. See Note 7, “Long-Term Debt”, for discussions on the October 2016 2.00% Convertible Senior Notes.
[6]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

CONSOLIDATED STATEMENTS OF STO9

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2016	Oct. 31, 2016	Dec. 31, 2015
Special Stock Shares Issued			100
Debt Instrument, Interest Rate, Stated Percentage				2.00%
Convertible Debt [Member]
Debt Instrument, Convertible, Carrying Amount of Equity Component				$ 402,500
Debt Instrument Convertible Carrying Amount Tax Portion Of The Equity Component				$ 11,900
Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member]
Purchase of noncontrolling interest in Subsidiary	[1]		$ (4,589)
IMTT [Member] | Quebec Marine Terminal [Member]
Equity interest acquired		33.30%
IMTT [Member] | Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member] | Quebec Marine Terminal [Member]
Purchase of noncontrolling interest in Subsidiary		$ (4,600)
Manager [Member]
Special Stock Shares Issued			100		100
[1]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss.

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Operating activities
Net income (loss)		$ 154,869		$ (113,807)		$ 1,039,283
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization of property and equipment		226,492		215,243		102,816
Amortization of intangible assets		65,425		101,435		42,695
Equity in earnings and amortization charges of investee		0		0		(26,391)
Equity distributions from investee		0		0		25,330
Gain from acquisition/divestiture of businesses		0		0		(1,027,181)
Amortization of debt financing costs		21,041		9,075		5,376
Amortization of debt discount		1,007		0		0
Adjustments to derivative instruments		(54,549)		(47,208)		(567)
Fees to Manager- related party		68,486		287,139		103,182
Equipment lease receivable, net		0		0		2,805
Deferred taxes		63,947		(58,734)		(27,942)
Pension expense		8,601		7,300		4,148
Other non-cash (income) expense, net		(1,370)		(1,047)		5,411
Changes in other assets and liabilities, net of acquisitions:
Restricted cash		525		722		35,858
Accounts receivable		(8,415)		5,418		1,645
Inventories		(2,343)		(84)		4,779
Prepaid expenses and other current assets		7,794		(6,964)		5,448
Due to Manager - related party		135		(33)		(11)
Accounts payable and accrued expenses		4,686		(8,002)		(12,446)
Income taxes payable		8,251		(5,926)		288
Pension contribution		(3,500)		0		(26,960)
Other, net		(762)		(3,371)		(5,951)
Net cash provided by operating activities		560,320		381,156		251,615
Investing activities
Acquisitions of businesses and investments, net of cash acquired		(69,168)		(266,895)		(1,222,266)
Proceeds from sale of business, net of cash divested		0		0		265,295
Return of investment in unconsolidated business		0		0		12,319
Purchases of property and equipment		(314,684)		(194,148)		(123,946)
Proceeds from insurance claim		11,068		0		0
Change in restricted cash		(84)		10,559		0
Other, net		(3,977)		1,668		(208)
Net cash used in investing activities		(376,845)		(448,816)		(1,068,806)
Financing activities
Proceeds from long-term debt		1,311,000		2,486,569		412,884
Payment of long-term debt		(1,476,228)		(2,554,552)		(548,431)
Proceeds from the issuance of shares		12,623		492,433		765,052
Dividends paid to common stockholders		(396,093)		(341,560)		(240,535)
Contributions received from noncontrolling interests		15,431		532		0
Purchase of noncontrolling interest		(9,909)		0		0
Distributions paid to noncontrolling interests		(4,630)		(2,546)		(62,538)
Offering and equity raise costs paid		(1,601)		(16,984)		(25,600)
Debt financing costs paid		(17,392)		(23,816)		(15,142)
Proceeds from the issuance of convertible senior notes		402,500		0		350,000
Change in restricted cash		5,587		5,166		(999)
Payment of capital lease obligations		(2,601)		(2,346)		(2,269)
Net cash (used in) provided by financing activities		(161,313)		42,896		632,422
Effect of exchange rate changes on cash and cash equivalents		211		(856)		(590)
Net change in cash and cash equivalents		22,373		(25,620)		(185,359)
Cash and cash equivalents, beginning of period		22,394	[1]	48,014		233,373
Cash and cash equivalents, end of period		44,767		22,394	[1]	48,014
Non-cash investing and financing activities:
Accrued financing costs		3		3		112
Accrued purchases of property and equipment		28,288		23,396		8,122
Acquisition of equipment through capital leases		0		398		3,744
Issuance of shares to Manager		135,345		218,645		101,345
Issuance of shares to independent directors		750		750		750
Issuance of shares for acquisition of business		0		0		115,000
Conversion of convertible senior notes to shares		4		25		0
Conversion of LLC interests to common stock	[2]	0		79		0
Conversion of LLC interests to additional paid in capital	[2]	0		2,428,334		0
Conversion of construction loan to term loan		0		0		60,360
Distributions payable to noncontrolling interests		42		33		441
Taxes (refund) paid, net		(898)		6,654		19,704
Interest paid		$ 108,737		$ 109,450		$ 69,256
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	See Note 9, “Stockholders’ Equity”, for discussion on LLC interests, common stock and additional paid in capital.

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business Macquarie Infrastructure Corporation is the successor to Macquarie Infrastructure Company LLC (MIC LLC) pursuant to the conversion (the Conversion) of MIC LLC from a Delaware limited liability company to a Delaware corporation on May 21, 2015. MIC LLC was formed on April 13, 2004. Except as otherwise specified, all references in this Form 10-K to “MIC” or the “Company” refer (i) from and after the time of the Conversion, to Macquarie Infrastructure Corporation and its subsidiaries and (ii) prior to the Conversion, to the predecessor MIC LLC and its subsidiaries. Except as otherwise specified, all references in this Form 10-K to “common stock” or “shares” refer (i) from and after the time of the Conversion, to common stock and (ii) prior to the Conversion, LLC interests. The Company is a party to a Management Services Agreement with Macquarie Infrastructure Management (USA) Inc. (the Manager), subject to the oversight and supervision of the Company’s Board of Directors. The Manager is a wholly-owned subsidiary within the Macquarie Group of companies, which is comprised of Macquarie Group Limited and its subsidiaries and affiliates worldwide. Macquarie Group Limited is headquartered in Australia and is listed on the Australian Stock Exchange. MIC, and MIC LLC prior to the Conversion, is treated as a corporation for tax purposes. The Company owns its businesses through its direct wholly-owned subsidiary MIC Ohana Corporation, the successor to Macquarie Infrastructure Company Inc. pursuant to the Conversion on May 21, 2015. The Company owns and operates a diversified portfolio of businesses that provide services to other businesses, government agencies and individuals primarily in the U.S. The businesses it owns and operates are: • International-Matex Tank Terminals (IMTT) • Atlantic Aviation • Contracted Power (CP): • MIC Hawaii segment:

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company consolidates investments where it has a controlling financial interest. The general condition for a controlling financial interest is ownership of a majority of the voting interest and, therefore, as a general rule, ownership, directly or indirectly, of over 50% of the outstanding voting shares is a condition for consolidation. In addition, if the Company demonstrates that it has the ability to direct policies and management, this may be also indication for consolidation. For investments in variable interest entities, the Company consolidates when it is determined to be the primary beneficiary of the variable interest entity. As of December 31, 2016, the Company was the primary beneficiary in seven solar facilities and two wind facilities in the U.S. and consolidated these projects accordingly. The Company accounts for 50% or less owned companies over which it has the ability to exercise significant influence using the equity method of accounting, otherwise the cost method is used. The Company’s share of net income or losses of equity investments is included in equity in earnings and amortization charges of investee in the consolidated statements of operations. Losses are recognized in other income (expense), net when a decline in the value of the investment is deemed to be other than temporary. In making this determination, the Company considers factors to be evaluated in determining whether a loss in value should be recognized, including the Company’s ability to hold its investment and inability of the investee to sustain an earnings capacity, which would justify the carrying amount of the investment. Subsequent to the IMTT Acquisition on July 16, 2014, the Company does not have any investments accounted for under the equity method of accounting on its consolidated balance sheet. From January 1, 2014 through July 15, 2014, the results of IMTT were accounted for under the equity method of accounting. From July 16, 2014 through December 31, 2014 and subsequent periods, the Company has consolidated the financial results of IMTT. Investment in unconsolidated business of $8.8 million and $8.3 million at December 31, 2016 and 2015, respectively, represent primarily a 20% ownership interest in a joint venture acquired in conjunction with the IMTT Acquisition on July 16, 2014. This investment is accounted for at cost on the consolidated balance sheet. Income from this investment is recorded in other income (expense), net, on the consolidated statements of operations. The preparation of the consolidated financial statements, which are in conformity with generally accepted accounting principles (GAAP) requires the Company to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. The Company evaluates these estimates and judgments on an ongoing basis and the estimates are based on experience, current and expected future conditions, third-party evaluations and various other assumptions that the Company believes are reasonable under the circumstances. Significant items subject to such estimates and assumptions include the carrying amount of property, equipment, land and leasehold improvements, intangibles and goodwill; assets and obligations related to employee benefits; and valuation of derivative instruments. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from the estimates and assumptions used in the financial statements and related notes. Acquisitions of businesses that the Company controls are accounted for under the purchase method of accounting. The amounts assigned to the identifiable assets acquired and liabilities assumed in connection with acquisitions are based on estimated fair values as of the date of the acquisition, with the remainder, if any, recorded as goodwill. The fair values are determined by the Company’s management, taking into consideration information supplied by the management of acquired entities and other relevant information. Such information includes valuations supplied by independent appraisal experts for significant business combinations. The valuations are generally based upon future cash flow projections for the acquired assets, discounted to present value. The determination of fair values require significant judgment both by management and outside experts engaged to assist in this process. The Company considers all highly liquid investments, including commercial paper issued by a counterparty with Standard & Poor rating of A1+, with a maturity of three months or less when purchased to be cash equivalents. The Company did not have any commercial paper at December 31, 2016 and 2015. Restricted cash on the consolidated balance sheets represents cash account agreements that require the businesses within the CP segment and the solar facilities in the MIC Hawaii segment that have long-term debt to maintain cash accounts restricted to fund operations, capital expenditures, debt service and make distributions to the Company and its partners. For these businesses, cash generated from operations is recorded in restricted cash upon receipt. Bayonne Energy Center (BEC), within the CP segment, also uses restricted cash to fund capital expenditures. The Company recorded $16.5 million of cash pledged as collateral in the consolidated balance sheet at December 31, 2016, of which $16.4 million was recorded within current assets. At December 31, 2015, the Company recorded $19.0 million of cash pledged as collateral in the consolidated balance sheet, of which $18.9 million was recorded within current assets. The remaining amounts are included in other noncurrent assets. The Company uses estimates to determine the amount of the allowance for doubtful accounts necessary to reduce billed and unbilled accounts receivable to their net realizable value. The Company estimates the required allowance by reviewing the status of past-due receivables and analyzing historical bad debt trends. Actual collection experience has not varied significantly from estimates primarily due to credit policies and a lack of concentration of accounts receivable. The Company writes off receivables deemed to be uncollectible to the allowance for doubtful accounts. Inventory consists principally of fuel purchased from various third-party vendors at Atlantic Aviation and the Hawaii Gas business and materials and supplies at all of the operating businesses. Fuel inventory is stated at the lower of cost or market. Materials and supplies inventory is valued at the lower of average cost or market. Inventory sold is recorded using the first-in-first-out method at Atlantic Aviation and an average cost method at Hawaii Gas. IMTT also has inventory for sale for its spill response activity business. This is carried at lower of average cost or market. Cash flows related to the sale of inventory are classified in net cash provided by operating activities in the consolidated statements of cash flows. The Company’s inventory balance at December 31, 2016 comprised $14.3 million of inventory held for sale and $17.2 million of materials and supplies. The Company’s inventory balance at December 31, 2015 comprised $14.3 million of inventory held for sale and $15.2 million of materials and supplies. Property, equipment and land are initially recorded at cost. Leasehold improvements are recorded at the initial present value of the minimum lease payments less accumulated amortization. Major renewals and improvements are capitalized while maintenance and repair expenditures are expensed when incurred. Interest expense relating to construction in progress is capitalized as an additional cost of the asset. The Company depreciates property, equipment and leasehold improvements over their estimated useful lives on a straight-line basis. Within the CP segment, depreciation expense for the district energy business was included in cost of services in the consolidated statements of operations prior to the Company’s divestiture of the business on August 21, 2014. The estimated economic useful lives range according to the table below: Buildings 10 to 68 years Leasehold and land improvements 5 to 40 years Machinery and equipment 3 to 62 years Furniture and Fixtures 3 to 15 years Goodwill consists of costs in excess of the aggregate purchase price over the fair value of tangible and identifiable intangible net assets acquired in business combinations. The cost of intangible assets with determinable useful lives is amortized over their estimated useful lives ranging as follows: Customer relationships 5 to 30 years Contractual arrangements 5 to 57 years Non-compete agreements 3 to 10 years Leasehold rights 25 years Trade names 20 years Technology 5 years Long-lived assets, including amortizable intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable. These events or changes in circumstances may include a significant deterioration of operating results, changes in business plans, or changes in anticipated future cash flows. If an impairment indicator is present, the Company evaluates recoverability by a comparison of the carrying amount of the assets to future undiscounted net cash flows expected to be generated by the assets. If the assets are impaired, the impairment recognized is measured by the amount by which the carrying amount exceeds the fair value of the assets. Fair value is generally determined by estimates of discounted cash flows or value expected to be realized in a third party sale. The discount rate used in any estimate of discounted cash flows would be the rate required for a similar investment of like risk. Goodwill is tested for impairment at least annually or when there is a triggering event that indicates impairment. For the annual impairment test, the Company can make a qualitative assessment of whether it is more likely than not that a reporting unit’s fair value is less than its carrying amount before applying the two-step goodwill impairment test, as discussed below. If an entity concludes it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, it need not perform the two-step impairment test. If an entity concludes that it is more likely than not that the fair value of reporting unit is less than its carrying amount, or if there is a triggering event that indicates impairment, the Company needs to perform the two-step impairment test. This requires management to make judgments in determining what assumptions to use in the calculation. The first step is to determine the estimated fair value of each reporting unit with goodwill. The reporting units of the Company, for purposes of the impairment test, are those components of operating segments for which discrete financial information is available and segment management regularly reviews the operating results of that component. When determining reporting units, components with similar economic characteristics are combined. The Company estimates the fair value of each reporting unit by estimating the present value of the reporting unit’s future discounted cash flows or value expected to be realized in a third party sale. If the recorded net assets of the reporting unit are less than the reporting unit’s estimated fair value, then no impairment is indicated. Alternatively, if the recorded net assets of the reporting unit exceed its estimated fair value, then goodwill is assumed to be impaired and a second step is performed. In the second step, the implied fair value of goodwill is determined by deducting the estimated fair value of all tangible and identifiable intangible net assets of the reporting unit from the estimated fair value of the reporting unit. If the recorded amount of goodwill exceeds this implied fair value, an impairment charge is recorded for the excess. Indefinite-lived intangibles, which consist of trademarks, are considered impaired when the carrying amount of the asset exceeds its implied fair value. The Company estimates the fair value of each trademark using the relief-from-royalty method that discounts the estimated net cash flows the Company would have to pay to license the trademark under an arm’s length licensing agreement. If the recorded indefinite-lived intangible is less than its estimated fair value, then no impairment is indicated. Alternatively, if the recorded intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. The Company capitalizes all direct costs incurred in connection with the issuance of debt as debt issuance costs. These costs are amortized over the contractual term of the debt instrument, which ranges from 5 to 23 years, using the effective interest method. From time to time the Company enters into interest rate derivative agreements to minimize potential variations in cash flows resulting from fluctuations in interest rates and their impact on its variable-rate debt. Since the fourth quarter of 2014, the Company’s Hawaii Gas business entered into commodity price hedges to mitigate the impact of fluctuations in propane prices on its cash flows. The Company accounts for derivatives and hedging activities in accordance with Accounting Standard Codification (ASC) 815 Derivatives and Hedging The Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and variable-rate senior debt, are carried at cost, which approximates their fair value because of either the short-term maturity, or competitive interest rates assigned to these financial instruments. Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. The Company places its cash and cash equivalents with financial institutions and its balances may exceed federally insured limits. The Company’s accounts receivable are mainly derived from fuel and gas sales and services rendered under contract terms with commercial and private customers located primarily in the United States. At December 31, 2016 and 2015, there were no outstanding accounts receivable due from a single customer that accounted for more than 10% of the total accounts receivable. Additionally, no single customer accounted for more than 10% of the Company’s revenue during the years ended December 31, 2016, 2015 and 2014. The assets and liabilities of IMTT’s Newfoundland and Quebec locations are translated from their local currency (Canadian dollars) to U.S. dollars at exchange rates in effect at the end of the year and consolidated statement of operations accounts are translated at average exchange rates for the year. Translation gains or losses as a result of changes in the exchange rate are recorded as a component of other comprehensive income (loss). Tolling agreements represent agreements with an off-taker where BEC agrees to sell 62.5% of its capacity, energy and ancillary services for fixed monthly tolling and capacity payments and monthly variable operation and maintenance (O&M) fees. Fixed payments received under these contracts were below prevailing market rates at the date of acquisition. The difference between the present value of the fixed payments and the present value of the market rates at the date of acquisition is recorded as a liability on the consolidated balance sheet as part of purchase accounting. This liability is amortized into revenue over a weighted average life of the tolling agreements of approximately thirteen years with approximately eleven years remaining at December 31, 2016. The Company calculates income (loss) per share using the weighted average number of common shares outstanding during the period. Diluted income (loss) per share is computed using the weighted average number of dilutive common equivalent shares outstanding during the period. Common equivalent shares consist of shares issuable upon conversion of the Company’s convertible senior notes (using the if-converted method), stock units granted to the Company’s independent directors and fees payable to the Manager that will be reinvested in shares by the Manager in a future period. Common equivalent shares are excluded from the calculation if their effect is anti-dilutive. The Company follows the requirements of ASC 220 Comprehensive Income The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller’s price to the buyer is fixed and determinable and collectability is probable. IMTT Contracts for the use of storage capacity at the various terminals predominantly have non-cancelable terms of one to five years. These contracts generally provide for payments for providing storage capacity throughout their term based on a fixed rate per barrel of capacity leased, as adjusted annually for inflation indices. Contract revenue is recognized over the term based on the rate specified in the contract. Revenue from the rendering of ancillary services (e.g., product movement (throughput), heating, blending, etc.) is recognized as the related services are performed based on contract rates. Throughput revenues in excess of those provided by contract are not recognized until the throughput quantity specified in the contract for the applicable period is exceeded. Payments received prior to the related services being performed or as a reimbursement for specific fixed asset additions or improvements related to a customer’s contract are recorded as deferred revenue and ratably recognized as revenues over the contract term; the noncurrent portion is included in other noncurrent liabilities. Environmental response services revenues are recognized as services are rendered. Revenue from IMTT is recorded in service revenue on the consolidated statements of operations. Atlantic Aviation Revenue from Atlantic Aviation is recorded in service revenue on the consolidated statements of operations. Services provided by Atlantic Aviation include: (i) Fuel services recognized when fuel has been delivered to the customer, collection of the resulting receivable is probable, persuasive evidence of an arrangement exists and the fee is fixed or determinable. Fuel services are recorded net of volume discounts and rebates; (ii) Certain fueling fees for fueling certain carriers with fuel owned by such carriers. Revenue from these transactions are recorded based on the service fee earned and does not include the cost of the carriers’ fuel; and (iii) Other services consisting principally of de-icing services, landing and fuel distribution fees as well as rental income for hangar and terminal use. Other fixed base operation (FBO) revenue is recognized as the services are rendered to the customer. CP Bayonne Energy Center (BEC) Revenue from BEC is recorded in product revenue on the consolidated statements of operations. With respect to BEC’s contracted capacity, revenue is recognized as energy, capacity and ancillary services are sold to the off-taker under the third-party tolling agreements, which are based on a fixed rate per megawatt (MW) of capacity and not subject to dispatch or utilization. A portion of the revenues under the tolling agreements are subject to annual increases. Revenues under the tolling agreements are subject to availability of capacity (subject to a historical rolling average forced outage factor). Variable operating and major maintenance revenues under the tolling agreements are a function of net plant output and a negotiated rate, which is adjusted annually based on historical plant experience. With respect to BEC’s residual capacity, revenue is recognized as energy, capacity and ancillary services are sold into the New York Independent System Operator (NYISO) energy market, which are based on prevailing market rates at the time such services are sold. Volumes of energy and ancillary services sold are subject to BEC’s market based dispatch from NYISO. Solar and wind facilities Revenue from the solar and wind facilities are recognized when the electricity is provided to the utility companies. Owners of the solar and wind facilities sell substantially all of the electricity generated at a fixed price to electric utilities pursuant to long-term (typically 20 – 25 years) power purchase agreements (PPAs). Customers are billed on a monthly-cycle basis. Revenue from the solar and wind facilities are recorded in product revenue on the consolidated statements of operations. District energy business (through the date sold) Revenue from cooling capacity and consumption was recognized at the time of performance of service. Cash received from customers for services to be provided in the future was recorded as unearned revenue and recognized over the expected service period on a straight-line basis. Revenue from the district energy business was recorded in service revenue on the consolidated statements of operations through the date of sale on August 21, 2014. MIC Hawaii Hawaii Gas Hawaii Gas recognizes revenue when products are delivered. Sales of gas to customers are billed on a monthly-cycle basis. Earned but unbilled revenue is accrued and included in accounts receivable and revenue based on the amount of gas that is delivered but not billed to customers from the latest meter reading or billed delivery date to the end of an accounting period. The related costs are charged to expense. Most revenue is based upon consumption; however, certain revenue is based upon a flat rate . The other businesses within MIC Hawaii consist of a mechanical contractor focused on designing and constructing energy efficient building infrastructure together with controlling interests in renewable and distributed power facilities including two facilities on Oahu. Revenue generated by the mechanical contractor business is recorded in service revenue and revenue generated by the renewable facilities are recorded in product revenue. At December 31, 2016, the signed contract backlog from the mechanical contractor business totaled approximately $75.0 million and is expected to be recognized into revenue within two to three years. The regulated utility operations of the Hawaii Gas business are subject to regulations with respect to rates, service, maintenance of accounting records, and various other matters by the Hawaii Public Utilities Commission (HPUC). The established accounting policies recognize the financial effects of the rate-making and accounting practices and policies of the HPUC. Regulated utility operations are subject to the provisions of ASC 980, Regulated Operations ASC 980 may, at some future date, be deemed inapplicable because of changes in the regulatory and competitive environments or other factors. If the Company were to discontinue the application of this guidance, the Company would be required to write-off its regulatory assets and regulatory liabilities and would be required to adjust the carrying amount of any other assets, including property, plant and equipment, that would be deemed not recoverable related to these affected operations. The Company believes its regulated operations in the Hawaii Gas business continue to meet the criteria of ASC 980 and that the carrying value of its regulated property, plant and equipment is recoverable in accordance with established HPUC rate-making practices. The Company accounts for income taxes using the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company and its more than 80% owned subsidiaries file a consolidated U.S. federal income tax return, including its allocated share of the taxable income from its solar and wind facilities. The investments in solar and wind facilities within the CP and the MIC Hawaii segments are held in various LLCs, which are treated as partnerships for income tax purposes. Prior to the IMTT Acquisition in July 2014, the Company’s consolidated income tax return did not include IMTT and the district energy business, both of which were less than 80% owned by the Company and each filed separate income tax returns. Subsequent to the Company’s acquisition of the remaining 50% interest in IMTT, IMTT became a wholly owned subsidiary and files as part of the Company’s consolidated federal income tax return. The district energy business continued to file separate income tax returns through 2014. The Company sold its interest in the district energy business on August 21, 2014. In assessing the need for a valuation allowance, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Certain reclassifications were made to the financial statements for the prior periods to conform to current year presentation. On January 5, 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business On November 17, 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash On February 25, 2016, FASB issued ASU No. 2016-02, Leases (Topic 842) On November 20, 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes On September 25, 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement Period Adjustments In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) • ASU 2015-14 (Issued August 2015) — Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date • ASU 2016-08 (Issued March 2016) — Principal versus Agent Consideration (Reporting Revenue Gross versus Net) • ASU 2016-10 (Issued April 2016) — Identifying Performance Obligations and Licensing • ASU 2016-12 (Issued May 2016) — Narrow-Scope Improvements and Practical Expedients • ASU 2016-20 (Issued December 2016) — Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers With the deferral, the new standard is effective for the Company on January 1, 2018. Early application is permitted to the original effective date of January 1, 2017. There are two adoption methods available for implementation of the standard related to the recognition of revenue from contracts with customers. Under one method, the new guidance is applied retrospectively to contracts for each reporting period presented, subject to allowable practical expedients. Under the other method, the new guidance is applied only to the most current period presented, recognizing the cumulative effect of the change as an adjustment to the beginning balance of retained earnings, and also requires additional disclosures comparing the results to the previous guidance. The Company is currently evaluating these adoption methods, the impact that this standard will have on the Company’s financial statements, and the changes to its systems, processes and internal controls to meet the reporting and disclosure requirements. Upon initial evaluation, the Company believes key changes in the standard that impact the Company’s revenue recognition relate to the allocation of contract revenues between various services and equipment, and the timing of when those revenues are recognized. The Company is still in the process of evaluating these impacts and other areas of the standard and its effect on the Company’s financial statements and related disclosures. The Company currently includes sales, excise and value-added taxes related to sales transactions within revenue on the consolidated statements of operations. Upon adoption of ASU 2014-09, the Company will exclude sales-based taxes collected on behalf of third parties from product revenue and include these amounts in cost of services and product sales. The result will be a reclassification on the consolidated statements of operations. ASU 2014-09 also introduces new qualitative and quantitative disclosure requirements about contracts with customers including revenue and impairments recognized, disaggregation of revenue and information about contract balance and performance obligations. Information is required about significant judgments and changes in judgments in determining the timing of satisfaction of performance obligations. Additional disclosures are required about assets recognized from the costs to obtain or fulfill a contract. The Company is still in the process of evaluating what disclosures will be required, but expects the level of disclosures related to revenue recognition to increase. On July 22, 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory, On April 7, 2015, the FASB issued ASU No. 2015-03, Interest — Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs On February 18, 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis

Income (Loss) per Share

Income (Loss) per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
[Income (Loss)] per Share	3. Income (Loss) per Share Following is a reconciliation of the basic and diluted income (loss) per share computations ($ in thousands, except share and per share data): Year Ended December 31, 2016 2015 2014 Numerator: Net income (loss) attributable to MIC $ 156,381 $ (108,537 ) $ 1,042,028 Interest expense attributable to convertible senior notes – July 2014, net of taxes (1) — — 3,016 Interest expense attributable to convertible senior notes – October 2016, net of taxes (4,523 ) — — Diluted net income (loss) attributable to MIC $ 151,858 $ (108,537 ) $ 1,045,044 Denominator: Weighted average number of shares outstanding: basic 80,892,654 77,997,826 62,990,312 Dilutive effect of restricted stock unit grants 9,589 — 12,637 Dilutive effect of fees to Manager-related party 549,404 — — Dilutive effect of convertible senior notes – July 2014 — — 1,922,616 Dilutive effect of convertible senior notes – October 2016 766,980 — — Weighted average number of shares outstanding: diluted 82,218,627 77,997,826 64,925,565 Income (loss) per share: Basic income (loss) per share attributable to MIC $ 1.93 $ (1.39 ) $ 16.54 Diluted income (loss) per share attributable to MIC $ 1.85 $ (1.39 ) $ 16.10 (1) For the year ended December 31, 2014, diluted income per share attributable to MIC does not include the after-tax impact of the write-off of deferred financing costs attributable to the July 2014 2.875% Convertible Senior Notes. If the after-tax impact of deferred financing costs were added back to net income for the year ended December 31, 2014, the diluted income per share attributable to MIC would have been $16.01. The effect of potentially dilutive shares for the year ended December 31, 2016 is calculated assuming that (i) the restricted stock unit grants totaling 8,604 (net of forfeitures of 2,151 restricted stock unit grants forfeited on September 30, 2016) provided to the independent directors on May 18, 2016 and restricted stock units grants of 991 provided to a new independent director on November 1, 2016, which will both vest during the second quarter of 2017, and the 8,660 restricted stock units provided to the independent directors on June 18, 2015, which vested during the second quarter of 2016, had been fully converted to shares on those grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes issued in October 2016 had been fully converted into shares on the date of issuance. The convertible senior notes issued in July 2014 were anti-dilutive for the year ended December 31, 2016. Due to the Company’s net loss for the year ended December 31, 2015, (i) the 8,660 restricted stock unit grants provided to the independent directors on June 18, 2015, which vested during the second quarter of 2016, and the 12,525 restricted stock unit grants provided to the independent directors on May 21, 2014, which vested during the second quarter of 2015; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued on July 15, 2014, were all anti-dilutive. The effect of potentially dilutive shares for the year ended December 31, 2014 is calculated assuming that (i) the 12,525 restricted stock unit grants provided to the independent directors on May 21, 2014, which vested during the second quarter of 2015, and the 12,910 restricted stock unit grants provided to the independent directors on May 20, 2013, which vested during the second quarter of 2014, had been fully converted to shares on those grant dates and (ii) the convertible senior notes that were issued on July 15, 2014 had been fully converted into shares on that date. The following represents the weighted average potential dilutive shares of common stock that were excluded from the diluted income (loss) per share calculation: Year Ended December 31, 2016 2015 2014 Restricted stock unit grants — 9,410 — Fees to Manager – related party (1) — 449,126 — Convertible senior notes – July 2014 4,177,097 4,160,717 — Total 4,177,097 4,619,253 — (1) Represents $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016. The weighted average potentially dilutive shares of common stock in the above table include shares assumed to have been reinvested in shares by the Manager in July 2015.

Property, Equipment, Land and L

Property, Equipment, Land and Leasehold Improvements	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Equipment, Land and Leasehold Improvements	4. Property, Equipment, Land and Leasehold Improvements Property, equipment, land and leasehold improvements at December 31, 2016 and 2015 consist of the following ($ in thousands): As of December 31, 2016 2015 Land $ 304,240 $ 291,521 Easements 131 131 Buildings 41,711 41,049 Leasehold and land improvements 673,122 590,646 Machinery and equipment 3,764,553 3,455,776 Furniture and fixtures 35,454 29,547 Construction in progress 233,184 203,146 5,052,395 4,611,816 Less: accumulated depreciation (705,859 ) (495,653 ) Property, equipment, land and leasehold improvements, net $ 4,346,536 $ 4,116,163 During the year ended December 31, 2016, the Company invested $69.2 million in acquisitions primarily consisting of an FBO, an 80 MW solar facility in Utah and a design-build mechanical contractor in Hawaii. Substantially all of the purchase price was preliminary allocated to property, equipment, land and leasehold improvements of $132.3 million, accounts receivable of $21.9 million, intangible assets of $19.1 million and goodwill of $6.8 million. The assets acquired were offset by debt assumed of $78.2 million, accounts payable and accrued expenses of $6.9 million and preliminary allocated to noncontrolling interest of $24.1 million. During the quarter ended March 31, 2015, Atlantic Aviation reassessed the useful lives of its leasehold and land improvements related to leases at certain airports to generally match these useful lives with the remaining lease terms plus extensions under Atlantic Aviation’s control. During the quarter ended March 31, 2015, as a result of this reassessment, the business performed an impairment analysis related to its leasehold and land improvements and recorded a non-cash impairment of $2.8 million, which was included in depreciation expense. In addition, during the quarter ended March 31, 2015, a non-cash impairment charge of $4.2 million was recorded due to a change in the lease terms at one base. This amount was included in depreciation expense.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	5. Intangible Assets Intangible assets at December 31, 2016 and 2015 consist of the following ($ in thousands): As of December 31, 2016 2015 Contractual arrangements $ 912,728 $ 901,807 Non-compete agreements 10,014 9,665 Customer relationships 348,678 340,425 Leasehold rights 350 350 Trade names 16,091 16,091 Technology 8,760 8,760 1,296,621 1,277,098 Less: accumulated amortization (407,650 ) (342,206 ) Intangible assets, net $ 888,971 $ 934,892 See Note 4, “Property, Equipment, Land and Leasehold Improvements”, for discussion on intangible assets and goodwill acquired during the year ended December 31, 2016. During the quarter ended March 31, 2015, Atlantic Aviation reassessed the useful lives of its contractual arrangements related to leases at certain airports to generally match these useful lives with the remaining lease terms plus extensions under Atlantic Aviation’s control. During the quarter ended March 31, 2015, as a result of this reassessment, the business performed an impairment analysis related to its contractual arrangements and recorded a non-cash impairment of $13.5 million, which was included in amortization expense. In addition, during the quarter ended March 31, 2015, a non-cash impairment charge of $17.8 million was recorded due to a change in the lease terms at one base. This amount was included in amortization expense. Amortization expense of intangible assets for the years ended December 31, 2016, 2015 and 2014 totaled $65.4 million, $101.4 million and $42.7 million, respectively. The estimated future amortization expense for amortizable intangible assets to be recognized are ($ in thousands): 2017 $ 60,828 2018 56,537 2019 53,588 2020 49,439 2021 46,995 Thereafter 614,093 Total $ 881,480 The goodwill balance as of December 31, 2016 is comprised of the following ($ in thousands): Goodwill acquired in business combinations, net of disposals, at $ 2,143,057 Accumulated impairment charges (123,200 ) Other (2,646 ) Balance at December 31, 2015 2,017,211 Goodwill related to 2016 acquisitions 6,837 Other 361 Balance at December 31, 2016 $ 2,024,409 The Company tests for goodwill impairment at the reporting unit level on an annual basis on October 1 st

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities, Current [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses at December 31, 2016 and 2015 consisted of the following ($ in thousands): As of December 31, 2016 2015 Payroll and related liabilities $ 29,851 $ 26,740 Purchase of property and equipment 11,669 8,045 Interest 13,153 10,684 Insurance 3,957 6,361 Property tax 6,046 4,670 Other taxes (1) 4,689 5,750 Other 14,369 16,277 $ 83,734 $ 78,527 (1) Other taxes primarily consists of sales and franchise taxes.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-Term Debt	7. Long-Term Debt The Company capitalizes its operating businesses separately using non-recourse, project finance style debt. All of the term debt facilities described below contain customary financial covenants, including maintaining or exceeding certain financial ratios, and limitations on capital expenditures and additional debt. The facilities include events of default, representations and warranties and other covenants that are customary for facilities of this type, including change of control, which will occur if the Macquarie Group, or any fund or entity managed by the Macquarie Group, fails to control a majority of the Borrower. For a description of related party transactions associated with the Company’s long-term debt, see Note 11, “Related Party Transactions”. At December 31, 2016 and 2015, the Company’s consolidated long-term debt comprised the following ($ in thousands): As of December 31, 2016 2015 IMTT $ 1,140,975 $ 1,127,223 Atlantic Aviation 449,691 604,609 CP 604,862 555,486 MIC Hawaii 200,744 180,000 MIC Corporate (1) 726,730 365,975 Total 3,123,002 2,833,293 Current portion (40,016 ) (40,099 ) Long-term portion 3,082,986 2,793,194 Unamortized deferred financing costs (2) (43,020 ) (46,669 ) Long-term portion less unamortized debt discount and deferred financing costs $ 3,039,966 $ 2,746,525 (1) At December 31, 2016, MIC Corporate included $376.8 million in long-term debt, net of the unamortized debt discount of $25.7 million, related to the $402.5 million convertible senior notes issued in October 2016. See further discussions below. (2) The weighted average remaining life of the deferred financing costs at December 31, 2016 was 6.2 years. The total undrawn capacity on the revolving credit facilities at IMTT, Atlantic Aviation, CP, MIC Hawaii and MIC Corporate was $1.4 billion at December 31, 2016 and February 21, 2017. At December 31, 2016, including the unamortized debt discount of $25.7 million related to the October 2016 2.00% Convertible Senior Notes, future maturities of long-term debt are ($ in thousands): 2017 $ 40,016 2018 51,086 2019 402,157 2020 95,084 2021 480,888 Thereafter 2,079,512 Total $ 3,148,743 MIC Corporate Senior Secured Revolving Credit Facility In July 2014, the Company entered into a five-year, $250.0 million senior secured revolving credit facility with a syndicate of banks and subsequently increased the aggregate commitments under its revolving credit facility to $410.0 million, with all terms remaining the same. During the year ended December 31, 2016, the Company drew down $482.0 million and repaid $498.0 million on its senior secured revolving credit facility primarily for general corporate purposes. At December 31, 2016, the senior secured revolving credit facility remained undrawn. July 2014 2.875% Convertible Senior Notes On July 15, 2014, the Company completed an underwritten public offering of a five-year, $350.0 million aggregate principal amount of 2.875% convertible senior notes to partially fund the IMTT Acquisition and for general corporate purposes. The notes are convertible, at the holder’s option, into the Company’s shares, initially at a conversion rate of 11.7942 shares per $1,000 principal amount (equivalent to an initial conversion price of approximately $84.79 per share, subject to adjustment), at any time on or prior to the close of business on the second scheduled trading day immediately preceding the maturity date. On July 15, 2016, the conversion rate increased to 12.0091 shares of common stock per $1,000 principal amount. The adjustment reflects the impact of dividends paid by the Company from July 15, 2015, the prior anniversary date of the convertible senior notes. The notes are the Company’s unsecured obligations and rank equal in right of payment with all of the Company’s existing and future senior unsecured indebtedness. The fair value of this convertible senior note at December 31, 2016 was approximately $407.0 million. These convertible senior notes fall within Level 1 of the fair value hierarchy. October 2016 2.00% Convertible Senior Notes On October 13, 2016, the Company completed an underwritten public offering of $350.0 million aggregate principal amount of 2.0% convertible senior notes due 2023. On October 28, 2016, the underwriters exercised in full, their option to issue an additional $52.5 million in convertible senior notes. The net proceeds of $392.4 million were partially used to repay a portion of the drawn balance under the revolving credit facility under the New AA Credit Agreement (see below), the full repayment of the outstanding balances on both the MIC senior secured and IMTT revolving credit facilities and the remaining proceeds used for general corporate purposes. The notes are convertible, at the holder’s option, only upon satisfaction of one or more conditions set forth in the indenture governing the notes. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of Company common stock or a combination thereof, at the Company’s election. The initial conversion rate is 8.9364 shares per $1,000 principal amount (equivalent to an initial conversion price of approximately $111.90 per share, subject to adjustment). The notes are not redeemable prior to maturity on October 1, 2023. The notes are the Company’s unsecured obligations and rank equal in right of payment with all of the Company’s existing and future senior unsecured indebtedness. The $402.5 million of convertible senior notes issued in October 2016 had an initial value of the principal amount recorded as a liability of $375.8 million, using an effective interest rate of 3.1%. The remaining $26.7 million of principal amount was allocated to the conversion feature and recorded in additional paid in capital as a component of stockholders’ equity. This amount represents a discount to the debt to be amortized through interest expense using the effective interest method through the maturity of the convertible senior notes. The Company also recorded $11.0 million in deferred financing costs from the issuance of the convertible senior notes, of which $729,000 was recorded as equity issuance costs as a component of stockholders’ equity. At December 31, 2016, the October 2016 Convertible Senior Notes consisted of the following ($ in thousands): Liability Component: Principal $ 402,500 Unamortized debt discount (25,741 ) Unamortized deferred financing costs (9,934 ) Net carrying amount $ 366,825 Equity Component $ 26,748 The fair value of this convertible senior note at December 31, 2016 was approximately $380.0 million. These convertible senior notes fall within Level 1 of the fair value hierarchy. For the year ended December 31, 2016, total interest expense recognized related to the convertible senior notes issued in October 2016 were ($ in thousands): Contractual interest expense $ 1,969 Amortization of debt discount 1,007 Amortization of deferred financing costs 306 Total interest expense $ 3,282 The key terms of the senior secured revolving credit facility and the convertible senior notes at December 31, 2016 are summarized in the table below. Facility Terms Senior Secured Revolving July 2014 October 2016 Total Committed Amount $410.0 million — — Amount Outstanding at December 31, 2016 Undrawn $350.0 million $376.8 million, net of unamortized discount of $25.7 million Maturity July 2019 July 2019 October 2023 Amortization Revolving, payable at maturity Payable at maturity or convertible at the holder’s option into the Company’s shares Payable at maturity or convertible at the holder’s option into cash, the Company’s shares or a combination thereof only upon satisfaction of one or more conditions set forth in the indenture Interest Rate LIBOR plus 1.75% at December 31, 2016 2.875% payable on January 15 and July 15 of each year 2.0% payable on April 1 and October 1 of each year Commitment Fees 0.275% at December 31, 2016 — — Security Secured Unsecured Unsecured IMTT On May 21, 2015, ITT Holdings LLC (ITT LLC), a direct subsidiary of IMTT Holdings LLC and an indirect subsidiary of the Company, entered into a Credit Agreement (the Credit Agreement), among ITT LLC, IMTT — Quebec Inc. and IMTT — NTL, LTD. as Canadian borrowers, SunTrust Bank as administrative agent and the lenders thereto. The Credit Agreement provides for (i) a $550.0 million unsecured revolving credit facility for ITT LLC and (ii) the Canadian dollar equivalent of a $50.0 million unsecured revolving credit facility for the Canadian borrowers. In addition, ITT LLC entered into a Note Purchase Agreement for the issuance of $325.0 million aggregate principal amount of 3.92% Guaranteed Senior Notes, Series A due 2025, and $275.0 million aggregate principal amount of 4.02% of Guaranteed Senior Notes, Series B due 2027 (together the senior notes). The senior notes are unsecured. Proceeds from the senior notes issuance and the revolving credit facility borrowings were used to repay all amounts under the existing IMTT credit agreement and were used to finance working capital needs, capital expenditures, acquisitions, distributions and for other general corporate purposes. In connection with this refinancing, $509.0 million of IMTT’s outstanding Gulf Opportunity Zone Bonds (GO Zone Bonds) and New Jersey Economic Development Authority Bonds (NJEDA Bonds and, together with the Go Zone Bonds, the Tax Exempt Bonds) were repurchased. The GO Zone Bonds were reissued and sold to certain lenders under the Credit Agreement. The NJEDA Bonds were financed with a new issuance of tax exempt bonds and sold to certain lenders under the Credit Agreement. IMTT entered into interest rate swap contracts, maturing in June 2021, with a total notional amount of $361.1 million. These swaps fully hedge the floating LIBOR interest rate risk associated with the tax-exempt bonds for six years at 1.677%. Revolving Credit Facilities The revolving credit facilities are used primarily to fund IMTT’s growth capital expenditures and for general corporate purposes. During the year ended December 31, 2016, IMTT drew down $108.0 million on its USD revolving credit facility for general corporate purposes and to fund capital expenditures, of which $76.0 million was repaid. At December 31, 2016, IMTT had $32.0 million drawn on its USD revolving credit facility. Through February 21, 2017, IMTT repaid $8.0 million drawn on its USD revolving credit facility resulting in an outstanding balance of $24.0 million. The key terms of IMTT’s U.S. dollar and Canadian dollar denominated revolving credit facilities at December 31, 2016 are summarized in the table below. Facility Terms USD Revolving Credit Facility CAD Revolving Credit Facility Total Committed Amount $550.0 million $50.0 million Amount Outstanding at $32.0 million Undrawn Maturity May 2020 May 2020 Amortization Revolving, payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 1.50% at December 31, 2016 Bankers’ Acceptances Rate plus 1.50% at December 31, 2016 Commitment Fees 0.225% at December 31, 2016 0.225% at December 31, 2016 Security Unsecured Unsecured Senior Notes The key terms of the senior notes at December 31, 2016 are summarized in the table below. Facility Terms Senior Notes, Series A Senior Notes, Series B Amount Outstanding at $325.0 million $275.0 million Maturity May 2025 May 2027 Amortization Payable at maturity Payable at maturity Interest Rate 3.92% per annum 4.02% per annum Security Unsecured Unsecured Louisiana Public Facilities Authority Bonds and Ascension Parish Bonds (LA Bonds) The key terms of the LA Bonds at December 31, 2016 are summarized in the table below. Facility Terms Louisiana Public The Industrial Louisiana Public Louisiana Public Louisiana Public Amount Outstanding at December 31, 2016 $50.0 million $165.0 million $85.0 million $90.9 million $81.8 million Maturity June 2043 June 2043 August 2046 December 2040 December 2040 Amortization Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Interest Rate One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% Security Unsecured Unsecured Unsecured Unsecured Unsecured New Jersey Economic Development Authority Bonds (NJEDA Bonds) The key terms of the NJEDA Bonds at December 31, 2016 are summarized in the table below. Facility Terms New Jersey Economic Development Authority Amount Outstanding at December 31, 2016 $36.3 million Maturity December 2027 Amortization Payable at maturity, subject to mandatory tender in May 2022 Interest Rate One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% Security Unsecured Atlantic Aviation On October 7, 2016, Atlantic Aviation FBO Inc. (AA FBO) completed the refinancing of its existing $595.9 million term loan and $70.0 million revolving credit facility. AA FBO entered into a new five-year first lien senior secured $400.0 million term loan facility and a new five year first lien senior secured $350.0 million revolving credit facility (the New AA Credit Agreement). The New AA Credit Agreement is guaranteed jointly and severally on a senior secured basis by Atlantic Aviation FBO Holdings LLC (Holdings) and certain subsidiaries of AA FBO. Proceeds from the new term loan facility, together with $200.0 million drawn on the revolving credit facility, were used primarily to fully repay the outstanding balance on the existing term loan facility. Subsequently, $175.0 million of the outstanding balance on the revolving credit facility was repaid. In December 2016, the business borrowed $23.0 million to partially fund the purchase of a hangar. The outstanding balance at December 31, 2016 was $48.0 million with $302.0 million of undrawn capacity. Through February 21, 2017, Atlantic Aviation repaid $18.0 million drawn on its revolving credit facility resulting in an outstanding balance of $30.0 million. The key terms of the term loan and revolving credit facilities at December 31, 2016 are summarized in the table below. Facility Terms Term Loan Facility Revolving Credit Facility Facilities $400.0 million senior secured first lien term loan (fully drawn at December 31, 2016) $350.0 million senior secured first lien revolving credit facility ($48.0 million outstanding at December 31, 2016) Maturity October 7, 2021 October 7, 2021 Amortization • 2.5% of the initial principal balance per annum for the first year; Revolving, payable at maturity • 5.0% of the initial principal balance per annum for the next two years; and • 7.5% of the initial principal balance per annum until maturity Interest Type Floating Floating Interest Rate • LIBOR plus 1.50% to 2.25% or Alternate Base Rate (ABR) plus 0.50% to 1.25%, in each case depending on total leverage ratio. ABR is the highest of (i) the prime rate, (ii) the federal funds rate plus 0.5% and (iii) one-month LIBOR plus 1.0% • LIBOR plus 1.50% to 2.25% or ABR plus 0.50% to 1.25%, in each case depending on total leverage ratio Commitment Fees — 0.25% to 0.35% on the undrawn portion, depending on total leverage ratio Facility Terms Term Loan Facility Revolving Credit Facility Covenants Maintenance of a maximum total leverage ratio; limitations on, among other things, distributions and other restricted payments, incurrence of debt, liens, fundamental changes, asset sales, investments, affiliate transactions and sale and leasebacks, in each case subject to certain exceptions. Maintenance of a maximum total leverage ratio; limitations on, among other things, distributions and other restricted payments, incurrence of debt, liens, fundamental changes, asset sales, investments, affiliate transactions and sale and leasebacks, in each case subject to certain exceptions. Collateral First priority security interest in (x) the equity securities of AA FBO and certain of its subsidiaries and (y) the personal and material real property of Holdings, AA FBO and certain of its subsidiaries (in each case subject to certain exceptions) First priority security interest in (x) the equity securities of AA FBO and certain of its subsidiaries and (y) the personal and material real property of Holdings, AA FBO and certain of its subsidiaries (in each case subject to certain exceptions) Mandatory Prepayment • With net proceeds from the sale of assets in excess of $10.0 million or from certain insurance recoveries in excess of $5.0 million, that are not reinvested • With net proceeds of debt issuances by Holdings, AA FBO and its restricted subsidiaries (other than certain permitted debt) CP BEC On April 1, 2015, the Company acquired BEC and assumed $509.1 million of amortizing term loan debt maturing in August 2021. BEC also had a $30.0 million revolving credit facility maturing in August 2019. The interest rate on both the term loan facility and any drawn amounts under the revolving credit facility was LIBOR plus 4.0%, with a 1.0% LIBOR floor. Through July 2015, the Company fully repaid the principal balance on the term loan debt. On August 10, 2015, BEC entered into a seven-year, $275.0 million term loan facility and a seven-year, $25.0 million revolving credit facility. A majority of the proceeds of the term loan were used to fully repay the outstanding balance under the MIC senior secured revolving credit facility. Concurrently, BEC entered into amortizing interest rate swap contracts with an original notional of $275.0 million. These contracts are scheduled to amortize concurrently with the term loan debt and fix the floating LIBOR interest rate for six years at 1.786%. The key terms of the term loan and revolving credit facilities of BEC at December 31, 2016 are summarized in the table below. Facility Terms Term Financing Revolving Credit Facility Total Committed Amount $275.0 million $25.0 million Amount Outstanding at December 31, 2016 $261.0 million Undrawn Maturity August 2022 August 2022 Amortization $10.0 million per annum paid in equal quarterly installments with the balance payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 2.125% from August 2015 to August 2020; and LIBOR plus 2.125% from August 2015 to August 2020; and LIBOR plus 2.375% from August 2020 through maturity LIBOR plus 2.375% from August 2020 through maturity Commitment Fee — 0.50% per annum Collateral First lien on all assets (subject to certain exceptions) First lien on all assets (subject to certain exceptions) Solar and wind facilities At December 31, 2016, the CP segment consisted of six solar facilities and two wind facilities with senior secured debt outstanding of $343.9 million consisting of $193.2 million in fixed rate term loans and $150.7 million floating rate term loan, of which $142.2 million is fixed with interest rate swaps. In December 2016, the business acquired an 80 MW solar facility and assumed $73.1 million of term loan debt, of which $8.5 million was floating rate term loan. This facility also had a $20.0 million senior secured revolving credit facility that remained undrawn. At December 31, 2016, the term loans have interest rates ranging from 4.00% to 5.60%, with a weighted average rate of 4.75% maturing from September 2023 through December 2036. The key terms of the term loans at the solar and wind facilities at December 31, 2016 are presented below. Facility Terms Term Loan Facilities Term Loan Facility Borrower Solar Facilities – Term Loans Wind Facilities – Term Loan Facilities $201.7 million outstanding balance at December 31, 2016 $142.2 million outstanding balance at December 31, 2016 Maturity September 2023 to December 2036 December 2027 Amortization Fully amortizing through maturity Fully amortizing through maturity Interest Type Fixed and Floating Floating Interest Rate Fixed: 4.0% to 5.6%; Floating: LIBOR plus 2.00% LIBOR plus 1.625% at December 31, 2016; The margin increases by 0.25% every five years through maturity Collateral First lien on the following: First lien on the following: • Project revenues; • All property and assets of the Borrower and project companies; and • Equity of the Borrower; • Equity interests in the Borrower • All property and assets of the Borrower; and • Insurance policies and claims or proceeds. Facility Terms Term Loan Facilities Term Loan Facility Mandatory Prepayment • With net proceeds that equal or exceed $250,000 to $500,000 from the sale of assets not used for replacement of assets; • With net proceeds that equal or exceed $500,000 from the sale of assets; • With insurance proceeds that exceed from $250,000 to $1.0 million not used to repair, restore or replace assets; • With insurance proceeds that exceed $10.0 million not used to repair, restore or replace assets; • With condemnation proceeds that exceed from $250,000 to $1.0 million not used to repair, restore or replace assets; and • With Guaranteed Performance commitment liquidated damages in excess of $250,000; and • With net proceeds from equity and certain debt issuances. • With amount necessary to reduce debt to within the revised projected debt service coverage ratio following a substantial change such as additional wind turbines not in engineers plan. MIC Hawaii Hawaii Gas On February 10, 2016, Hawaii Gas completed the refinancing of its existing $80.0 million term loan and $60.0 million revolving credit facility. The new, five-year facilities include a reduction in interest rates on the term loan and revolving credit facility of 0.50% and 0.25%, respectively, compared with the prior facilities. The $80.0 million term loan bears interest at a variable rate of LIBOR plus an applicable margin between 1.0% and 1.75% and initially set at 1.75%. The variable rate component of the debt is fixed at 0.99% at December 31, 2016 using an interest rate swap contract through February 2020. The revolving credit facility bears interest at a variable rate of LIBOR plus an applicable margin between 1.0% and 1.75% and initially set at 1.25% and will remain unhedged. The key terms of the term loan, senior secured notes and revolving credit facility of Hawaii Gas at December 31, 2016 are summarized in the table below. Facility Terms Holding Company Debt Operating Company Debt Borrowers HGC Holdings LLC (HGC) The Gas Company, LLC (TGC) Facilities $80.0 million Term Loan (fully drawn at December 31, 2016) $100.0 million Senior Secured Notes (fully drawn at December 31, 2016) $60.0 million Revolving Credit Facility (undrawn at December 31, 2016) Maturity February 2021, subject to two 1-year extensions at borrower’s option August 2022 February 2021, subject to two 1-year extensions at borrower’s option Amortization Payable at maturity Payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 1.75% or Base Rate: 0.75% above the greater of the prime rate or the federal funds rate plus 0.5% 4.22% payable semi-annually LIBOR plus 1.25% or Base Rate: 0.25% above the greater of the prime rate or the federal funds rate plus 0.5% Commitment Fees ___ ___ 0.225% on the undrawn portion Collateral First lien on all assets of HGC and its subsidiaries First lien on all assets of TGC and its subsidiaries First lien on all assets of TGC and its subsidiaries Other Businesses In July 2016, the solar facilities in Hawaii entered into a ten year, $18.0 million amortizing term loan facility. The interest rate on this term loan facility floats at LIBOR plus 2.0%. The interest rate was fixed at 3.38% using an interest rate swap contract through June 30, 2026. At December 31, 2016, the outstanding balance on the term loan was $17.5 million. On August 31, 2016, the Company acquired a design-build mechanical contractor business and assumed $3.4 million in long-term debt. At December 31, 2016, the balance outstanding on this facility was $3.2 million.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	8. Derivative Instruments and Hedging Activities From time to time the Company enters into interest rate agreements to minimize potential variations in cash flows resulting from fluctuations in interest rates and their impact on its variable-rate debt. The Company does not enter into derivative instruments for any purpose other than economic interest rate hedging. That is, the Company does not speculate using derivative instruments. In addition, the Company’s Hawaii Gas business enters into commodity price hedges to mitigate the impact of fluctuations in propane prices on its cash flows. By using derivative financial instruments to hedge exposures to changes in interest rates, the Company exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is positive, the counterparty owes the Company, which creates credit risk for the Company. Conversely, when the fair value of a derivative contract is negative, the Company owes the counterparty and, therefore, it does not possess credit risk. The Company minimizes the credit risk in derivative instruments by entering into transactions with creditworthy counterparties. Market risk is the adverse effect on the value of a financial instrument that results from a change in interest rates. The market risk associated with interest rates is managed by establishing and monitoring parameters that limit the types and degree of market risk that may be undertaken. Interest Rate Contracts The Company and certain of its businesses have in place variable-rate debt. Management believes that it is prudent to limit the variability of a portion of the business’ interest payments. To meet this objective, the Company enters into interest rate agreements, primarily using interest rate swaps and from time to time using interest rate caps, to manage fluctuations in cash flows resulting from interest rate risk on a portion of its debt with a variable-rate component. Interest rate swaps change the variable-rate cash flow exposure on the debt obligations to fixed cash flows. Under the terms of the interest rate swaps, the Company receives variable interest rate payments and makes fixed interest rate payments, thereby creating the equivalent of fixed-rate debt for the portion of the debt that is swapped. At December 31, 2016, the Company had $3.1 billion of current and long-term debt, of which $1.4 billion was economically hedged with interest rate contracts, $1.6 billion was fixed rate debt and $88.4 million was unhedged. At December 31, 2015, the Company had $2.8 billion of current and long-term debt, of which $1.6 billion was economically hedged with interest rate contracts, $1.2 billion was fixed rate debt and $16.0 million was unhedged. The Company elected to discontinue hedge accounting in 2009. In prior periods, when the Company applied hedge accounting, changes in the fair value of derivatives that effectively offset the variability of cash flows on the Company’s debt interest obligations were recorded in other comprehensive income or loss. From the dates that hedge accounting was discontinued, all movements in the fair value of the interest rate swaps are recorded directly through earnings. As interest payments are made, a portion of the other comprehensive loss recorded under hedge accounting is also reclassified into earnings. As of December 31, 2014, the other comprehensive loss was fully amortized. IMTT On June 1, 2015, IMTT, as part of the IMTT refinancing in May 2015, entered into interest rate swap contracts, maturing in June 2021, with a total notional amount of $361.1 million. These swaps fully hedge the floating LIBOR interest rate risk associated with the tax-exempt bonds for six years at 1.677%. Concurrent with the refinancing, IMTT paid $31.4 million in interest rate swap breakage fees associated with the termination of out-of-the-money interest rate swap contracts related to prior debt facilities. Atlantic Aviation In October 2016, Atlantic Aviation entered into five-year senior secured $400.0 million term loan facility. The interest rate on the term loan facility floats at LIBOR plus an applicable margin between 1.50% and 2.25%. The term loan facility amortizes 2.5% for the first year, 5.0% for the next two years and 7.5% through maturity of the initial principal balance. On October 21, 2016, the business entered into $400.0 million notional interest rate caps with a strike price of 1.0% to hedge the one month LIBOR floating rate interest exposure on the new Atlantic Aviation term loan facility. The notional amount on the interest rate cap will remain at $400.0 million through maturity in September 2021. The business paid $8.6 million in upfront premiums to enter into the caps. As part of the refinancing, Atlantic Aviation paid $17.8 million in interest rate swap breakage fees associated with the termination of out-of-the-money interest rate swap contracts related to the prior term loan facility. CP BEC On April 1, 2015, the Company acquired BEC and assumed $509.1 million of amortizing term loan debt and interest rate swaps with a fair value of $21.5 million maturing in August 2021. The term loan facility bears interest of LIBOR plus 4.0%, with a 1.0% LIBOR floor. The interest rates swaps partially hedge the floating interest rate exposure of the term loan at a fixed rate of 3.455% through December 31, 2016 with periodic step-ups through maturity. Through July 2015, the Company fully repaid the principal balance on the term loan debt. Concurrently, the Company paid $19.2 million in interest rate swap breakage fees associated with the termination of out-of-the money interest rate swap contracts. On August 10, 2015, BEC entered into a seven year, $275.0 million term loan facility. The interest rate on this term loan facility floats at LIBOR plus 2.125% at December 31, 2016. Concurrently, BEC entered into amortizing interest rate swap contracts with an original notional of $275.0 million. These contracts are scheduled to amortize concurrently with the term loan debt and fix the floating LIBOR interest rate for six years at 1.786%. Wind facilities During 2014, in conjunction with the acquisition of the wind facility located in Idaho, the Company assumed $163.9 million in amortizing term loan debt that will mature in December 2027. The interest rate on the outstanding debt balance floats at LIBOR plus a fixed margin. The floating rate has been fixed using amortizing interest rate swap contracts that are scheduled to equal the total principal balance outstanding on all of the term loan facilities until maturity. On June 3, 2015, the term loan facility was amended to reduce the cost of borrowings. The margin on the floating interest rate decreased from 2.75% to 1.625% with all other terms remaining substantially unchanged. The floating interest rate on the amortizing debt balance has been fixed using interest rate swap contracts. A portion of the interest rate swap contracts were amended increasing the fixed rate by 0.20%. The weighted average rate fixed with the interest rate swap contracts and margin was 4.759% at December 31, 2016. MIC Hawaii In February 2016, in conjunction with the refinancing, Hawaii Gas entered into a new interest rate swap contract for an $80.0 million notional that took effect on August 8, 2016, upon the maturity of the existing interest rate swap, and expires on February 8, 2020. This new interest rate swap fixes the interest rate on the $80.0 million term loan at 2.74% as of December 31, 2016. The solar facilities in MIC Hawaii entered into a ten year, $18.0 million amortizing term loan facility in July 2016. The interest rate on this term loan facility floats at LIBOR plus 2.0%. Concurrently, it entered into an amortizing interest rate swap contract with an original notional value of $18.0 million. The contract is scheduled to amortize concurrently with the term loan and fixes the interest rate at 3.38% as of December 31, 2016. Commodity Price Hedges The risk associated with fluctuations in the prices at Hawaii Gas, a business within the MIC Hawaii reportable segment, pays for propane is principally a result of market forces reflecting changes in supply and demand for propane and other energy commodities. Hawaii Gas’ gross margin (revenue less cost of product sales excluding depreciation and amortization) is sensitive to changes in propane supply costs and Hawaii Gas may not always be able to pass through product cost increases fully or on a timely basis, particularly when product costs rise rapidly. In order to reduce the volatility of the business’ propane market price risk, Hawaii Gas has used and expects to continue to use over-the-counter commodity derivative instruments including price swaps. Hawaii Gas does not use commodity derivative instruments for speculative or trading purposes. Over-the-counter derivative commodity instruments used by Hawaii Gas to hedge forecasted purchases of propane are generally settled at expiration of the contract. Financial Statement Location Disclosure for Derivative Instruments The Company measures derivative instruments at fair value using the income approach which discounts the future net cash settlements expected under the derivative contracts to a present value. These valuations use primarily observable (level 2) inputs, including contractual terms, interest rates and yield curves observable at commonly quoted intervals. Assets (Liabilities) (1) Balance Sheet Location 2016 2015 Fair value of derivative instruments – current assets $ 5,514 $ — Fair value of derivative instruments – noncurrent assets 30,781 1,810 Total derivative contracts – assets $ 36,295 $ 1,810 Fair value of derivative instruments – current liabilities $ (9,297 ) $ (19,628 ) Fair value of derivative instruments – noncurrent liabilities (5,966 ) (15,698 ) Total derivative contracts – liabilities $ (15,263 ) $ (35,326 ) (1) Fair value measurements at reporting date were made using significant other observable inputs (level 2). Amount of Gain (Loss) Recognized in Financial Statement Account 2016 2015 2014 Interest expense – interest rate caps $ 8,124 $ — $ (1 ) Interest expense – interest rate swaps (1) (13,107 ) (28,454 ) (19,483 ) Cost of product sales – commodity swaps 13,914 (6,458 ) (571 ) Other expense – commodity swaps — — (2,541 ) Total $ 8,931 $ (34,912 ) $ (22,596 ) (1) Interest expense for the year ended December 31, 2014 includes $18.6 million of derivative losses and $856,000 for amounts reclassified from accumulated other comprehensive loss for the interest rate swap contracts. All of the Company’s derivative instruments are collateralized by the assets of the respective businesses.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders’ Equity	9. Stockholders’ Equity Classes of Stock The Company is authorized to issue (i) 500,000,000 shares of common stock, par value $0.001 per share, (ii) 100 shares of special stock, par value $0.001 per share and (iii) 100,000,000 shares of preferred stock, par value $0.001 per share. At December 31, 2016, the Company had 82,047,526 shares of common stock issued and outstanding and 100 shares of special stock issued and outstanding. There was no preferred stock issued or outstanding at December 31, 2016. Each outstanding share of common stock of the Company is entitled to one vote on any matter with respect to which holders of shares are entitled to vote. Upon consummation of the Conversion on May 21, 2015, each issued and outstanding LLC interest of MIC LLC was converted into one share of common stock of the Company. The Company also issued 100 shares of special stock to its Manager. The sole purpose for the issuance of special stock to the Manager was to preserve the Manager’s previously-existing right to appoint one director to serve as the chairman of the board of directors, which right would otherwise have been lost upon the Conversion. The special stock is not listed on any stock exchange and is non-transferable. Holders of special stock are not entitled to any dividends or to share in any distribution of assets upon the liquidation or dissolution of the Company. At May 21, 2015, upon consummation of the Conversion, the Company made a non-cash reclassification of $79,000 from LLC interests to common stock, par value $0.001 per share, with the remaining balance of LLC interests reclassified to additional paid in capital for the presentation of the consolidated balance sheet. 2016 Omnibus Employee Incentive Plan On May 18, 2016, the Company adopted the 2016 Omnibus Employee Incentive Plan (Plan). The Plan provides for the issuance of equity awards covering up to 500,000 shares of common stock to attract, retain, and motivate employees, consultants and others who perform services for the Company and its subsidiaries. Under the Plan, the Compensation Committee determines the persons who will receive awards, the time at which they are granted and the terms of the awards. Type of awards include stock options, stock appreciation rights, restricted stock, restricted stock units, dividend equivalent rights, cash-based awards and other stock-based awards. At December 31, 2016, there were no awards outstanding under this Plan. Shelf Registration Statement Renewal On April 5, 2016, the Company filed an automatic shelf registration statement on Form S-3 (shelf) with the SEC to issue and sell an indeterminate amount of its common stock, preferred stock and debt securities in one or more future offerings. At the Market (ATM) Program On June 24, 2015, the Company entered into an equity distribution agreement providing for the sale by the Company, from time to time, of shares of its common stock having an aggregate gross offering price of up to $400.0 million. Sales of shares may be made in privately negotiated transactions and/or any other method permitted by law, including sales deemed to be an “at the market” offering, which includes sales made directly on the New York Stock Exchange or sales made to or through a market maker other than on an exchange. Under the terms of the equity distribution agreement, the Company may also sell shares to any sales agent as principal for its own account. The Company is under no obligation to sell shares under the ATM Program. Through December 31, 2016, the Company sold 153,692 shares of common stock pursuant to the agreement for net proceeds of $12.6 million (after commissions and fees). MIC Direct The Company maintains a dividend reinvestment/direct share purchase program, named “MIC Direct”, that allows for the issuance of up to 1.0 million additional shares of common stock to participants in this program. At December 31, 2016, 935,101 shares remained unissued under MIC Direct. The Company may also choose to fill requests for reinvestment of dividends or share purchases through MIC Direct via open market purchases. Equity Offerings On March 2, 2015, the Company completed an underwritten public offering of 5,312,500 shares. On March 12, 2015, an additional 796,875 shares were sold pursuant to the exercise of the underwriters’ over-allotment option. The proceeds from the offering of $471.6 million, net of underwriting fees and expenses, were partially used to fund the acquisition of BEC on April 1, 2015 and for general corporate purposes. On July 15, 2014, the Company completed an underwritten public offering of 10,000,000 shares and an additional 1,500,000 shares pursuant to the exercise of the underwriters’ over-allotment option. The Company received proceeds from the offering of $739.2 million, net of underwriting fees and expenses, which were used to partially fund the IMTT Acquisition and for general corporate purposes. Accumulated Other Comprehensive Loss Cash Flow (1) Post-Retirement (2) Translation (3) Total Noncontrolling Total Balance at December 31, 2013 $ (636 ) $ (8,021 ) $ (46 ) $ (8,703 ) $ 258 $ (8,445 ) Reclassification of realized losses of derivatives into earnings 636 — — 636 (258 ) 378 Change in post-retirement benefit — (10,816 ) — (10,816 ) — (10,816 ) Translation adjustment — — (4,813 ) (4,813 ) 2,146 (2,667 ) Balance at December 31, 2014 $ — $ (18,837 ) $ (4,859 ) $ (23,696 ) $ 2,146 $ (21,550 ) Change in post-retirement benefit — 4,049 — 4,049 — 4,049 Translation adjustment — — (9,671 ) (9,671 ) 3,877 (5,794 ) Balance at December 31, 2015 $ — $ (14,788 ) $ (14,530 ) $ (29,318 ) $ 6,023 $ (23,295 ) Change in post-retirement benefit — (2,017 ) — (2,017 ) — (2,017 ) Translation adjustment — — 2,375 2,375 (1,434 ) 941 Purchase of noncontrolling (4) — — — — (4,589 ) (4,589 ) Balance at December 31, 2016 $ — $ (16,805 ) $ (12,155 ) $ (28,960 ) $ — $ (28,960 ) (1) Reclassification of realized losses of derivatives is composed of (i) pre-tax derivative losses into interest expense of $856,000 and the related tax benefit of $340,000 in the consolidated statements of operations; and (ii) pre-tax derivative losses of $185,000 as an adjustment to investment in unconsolidated business, and an adjustment to deferred taxes of $65,000, in the consolidated balance sheet for the year ended December 31, 2014. For the year ended December 31, 2014, the Company wrote-off $162,000 for the amount related to the investment in unconsolidated business and related taxes of $57,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (2) Change in post-retirement benefit plans is presented net of tax benefit of $1.4 million, tax expense of $2.7 million and tax benefit of $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, change in post-retirement benefit plans also includes a write-off of the remaining balance of $6.5 million and the related taxes of $2.3 million, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (3) Translation adjustment is presented net of tax expense of $618,000 and tax benefits of $3.9 million and $2.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, translation adjustment also includes a write-off of the remaining balance of $66,000 and the related taxes of $23,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (4) On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss. Dividends Declared Period Covered $ per Record Date Payable Date February 17, 2017 Fourth quarter 2016 $ 1.31 March 3, 2017 March 8, 2017 October 27, 2016 Third quarter 2016 1.29 November 10, 2016 November 15, 2016 July 28, 2016 Second quarter 2016 1.25 August 11, 2016 August 16, 2016 April 28, 2016 First quarter 2016 1.20 May 12, 2016 May 17, 2016 February 18, 2016 Fourth quarter 2015 1.15 March 3, 2016 March 8, 2016 October 29, 2015 Third quarter 2015 1.13 November 13, 2015 November 18, 2015 July 30, 2015 Second quarter 2015 1.11 August 13, 2015 August 18, 2015 April 30, 2015 First quarter 2015 1.07 May 14, 2015 May 19, 2015 February 17, 2015 Fourth quarter 2014 1.02 March 2, 2015 March 5, 2015 October 27, 2014 Third quarter 2014 0.98 November 10, 2014 November 13, 2014 July 3, 2014 Second quarter 2014 0.95 August 11, 2014 August 14, 2014 April 28, 2014 First quarter 2014 0.9375 May 12, 2014 May 15, 2014 February 18, 2014 Fourth quarter 2013 0.9125 March 3, 2014 March 6, 2014 The declaration and payment of any future dividends will be subject to a decision of the Company’s Board of Directors. The Board will take into account such matters as the state of the capital markets and general business conditions, the Company’s financial condition, results of operations, capital requirements, capital opportunities and any contractual, legal and regulatory restrictions on the payment of dividends by the Company to its stockholders or by its subsidiaries to the Company, and any other factors that it deems relevant, subject to maintaining a prudent level of reserves and without creating undue volatility in the amount of such dividends where possible. In particular, each of the Company’s businesses has debt commitments and restrictive covenants, which must be satisfied before any of them can make distributions to the Company. In addition, the Company’s senior secured credit facility contains restrictions on the Company’s ability to pay dividends. Although historically the Company has declared cash dividends on its shares, any or all of these factors or other factors could result in the modification of the dividend policy, or the reduction, modification or elimination of its dividend in the future. The dividends paid have been recorded as a reduction to additional paid in capital, subsequent to the Conversion (and as a reduction to LLC interests prior to the Conversion), in the stockholders’ equity section of the consolidated balance sheets. Independent Director Equity Plan In 2014, MIC adopted, and MIC’s stockholders approved, the 2014 Independent Directors Equity Plan (2014 Plan) to replace the 2004 Independent Directors Equity Plan, which expired in December 2014. The purpose of this plan is to promote the long-term growth and financial success of the Company by attracting, motivating and retaining independent directors of outstanding ability. Only the Company’s independent directors may participate in the 2014 Plan. The only type of award that may be granted under the 2014 Plan is an award of director shares. Each share is an unsecured promise to transfer one share on the settlement date, subject to satisfaction of the applicable terms and conditions. The maximum number of shares available for issuance under the 2014 Plan is 300,000 shares, of which 281,745 shares remain available for issuance at December 31, 2016. The aggregate grant date fair value of awards granted to an independent director during any single fiscal year (excluding awards made at the election of the independent director in lieu of all or a portion of annual and committee cash retainers) may not exceed $350,000. The 2014 Plan does not provide a formula for the determination of awards and the Compensation Committee will have the authority to determine the size of all awards under the 2014 Plan, subject to the limits on the number of shares that may be granted annually. Since 2014, the Company has granted and issued the following stock to the Board of Directors under the Plans: Date of Grant Stock Units (1) Price of Stock Date of Vesting May 21, 2014 12,525 $ 59.89 May 19, 2015 June 18, 2015 (2) 8,660 86.61 May 17, 2016 May 18, 2016 (2) (3) 8,604 69.72 (4) November 1, 2016 (2) (5) 991 81.93 (4) (1) Stock units granted refer (i) from and after the time of the Conversion, to common stock and (ii) prior to the Conversion, LLC interests. (2) Restricted stock units granted under the 2014 Plan. (3) Restricted stock units are net of forfeitures of 2,151 restricted stock units due to the retirement of an independent director on September 30, 2016. (4) Date of vesting will be the day immediately preceding the 2017 annual meeting of the Company’s stockholders. (5) Represents additional restricted stock unit grants to a new independent director.

Reportable Segments

Reportable Segments	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Reportable Segments	10. Reportable Segments At December 31, 2016, the Company’s businesses consist of four reportable segments: IMTT, Atlantic Aviation, CP and MIC Hawaii. Effective July 16, 2014, the date of the IMTT Acquisition, the Company consolidated the financial results of IMTT and IMTT became a reportable segment. Prior to July 16, 2014, the Company had a 50% investment in IMTT, which was accounted for under the equity method of accounting. The Company recorded equity in earnings and amortization charges of investees of $26.1 million from January 1, 2014 through July 15, 2014. This comprises the Company’s 50% share of IMTT’s net income offset by step-up depreciation and amortization charges in connection with the initial 50% investment in IMTT in May 2006. The unaudited pro forma selected consolidated financial data set forth below gives effect to the IMTT Acquisition as if it had occurred as of January 1, 2014. The pro forma adjustments give effect to the IMTT Acquisition based upon the acquisition method of accounting in accordance with U.S. GAAP. The selected unaudited pro forma consolidated financial data is presented for illustrative purposes only and is not necessarily indicative of the results of operations of future periods or results of operations that actually would have been realized had the Company and IMTT been consolidated during the period presented ($ in thousands): Year Ended Revenue $ 1,662,451 Net income attributable to MIC (1) 77,923 (1) The tax rate used to calculate net income attributable to MIC was 35.0%. Financial information for IMTT’s business as a whole is presented below for periods prior to July 16, 2014, where the Company accounted for the investment in IMTT under the equity method of accounting ($ in thousands): As of, and for the (1) Revenue $ 311,533 Net income $ 57,725 Interest expense, net 16,375 Provision for income taxes 38,265 Depreciation and amortization 40,922 Pension expense 4,025 Other non-cash expenses 112 EBITDA excluding non-cash items (2) $ 157,424 Capital expenditures paid $ 59,868 Property, equipment, land and leasehold improvements, net 1,289,245 Total assets 1,415,378 (1) Amounts represent financial position of IMTT business prior to July 16, 2014, the date of the IMTT Acquisition. (2) The Company defines EBITDA excluding non-cash items as net income (loss) or earnings — the most comparable GAAP measure IMTT IMTT provides bulk liquid storage, handling and other services in North America through ten terminals located in the United States, one terminal in Quebec, Canada and one partially owned terminal in Newfoundland, Canada. IMTT derives the majority of its revenue from storage and handling of petroleum products, various chemicals, renewable fuels, and vegetable and animal oils. Based on storage capacity, IMTT operates one of the largest third-party bulk liquid terminals businesses in the United States. Revenue from IMTT is included in service revenue. Atlantic Aviation Atlantic Aviation derives the majority of its revenues from fuel delivery services and from other airport services, including de-icing and aircraft hangar rental. All of the revenue of Atlantic Aviation is generated at airports in the U.S. At December 31, 2016, the business operates at 69 airports. Revenue from Atlantic Aviation is included in service revenue. CP The CP business segment derives revenue from solar, wind and gas-fired power facilities. Revenues from the solar, wind and gas-fired power facilities are included in product revenue. As of December 31, 2016, the Company has controlling interests in six utility-scale solar photovoltaic facilities, two wind facilities and 100% ownership of a gas-fired facility that are located in the United States. The solar and wind facilities that are operational at December 31, 2016 have an aggregate generating capacity of 340 megawatt (MW) of wholesale electricity to utilities. These facilities sell substantially all of the electricity generated, subject to agreed upon pricing formulas, to electric utilities pursuant to long-term (typically 20 – 25 years) PPAs. These projects are held in LLCs, and are treated as partnerships for income tax purposes, with co-investors. The acquisition price on these projects can vary depending on, among other things, factors such as the size of the project, PPA terms, eligibility for tax incentives, debt package, operating cost structure and development stage. A completed project takes out all of the construction risk, testing and costs associated with construction contracts. The Company has certain rights to make decisions over the management and operations of these solar and wind facilities. The Company has determined that it is appropriate to consolidate these projects, with the co-investors’ interest reflected as noncontrolling interests in the consolidated financial statements. On April 1, 2015, the Company acquired 100% of BEC. As a result of this transaction, the financial results of BEC have been consolidated as part of CP segment since the acquisition date. BEC is a 512 MW gas-fired facility located in Bayonne, New Jersey, adjacent to IMTT’s Bayonne facility. BEC has tolling agreements with a creditworthy off-taker for 62.5% of its power generating capacity and power produced is delivered to New York City via a dedicated transmission cable under New York Harbor. The tolling agreements generate revenue whether or not the facility is in use for power production. In addition to revenue related to the tolling agreement and capacity payments from the grid operator, BEC generates an energy margin when the facility is dispatched. MIC Hawaii Effective the quarter ended September 30, 2016, the Company combined its businesses and projects in Hawaii into a single segment, consistent with how the Company is managing those operations. Prior to the third quarter of 2016, MIC Hawaii consisted solely of Hawaii Gas. MIC Hawaii now comprises: Hawaii Gas, Hawaii’s only government-franchised gas utility and an unregulated liquefied petroleum gas distribution business providing gas and related services to commercial, residential and governmental customers; a mechanical contractor focused on designing and constructing energy efficient and related building infrastructure; and controlling interests in renewable and distributed power facilities including two facilities on Oahu. Revenue from Hawaii Gas and the renewable power facilities are recorded in product revenue. Revenue from the mechanical contractor business is recorded in service revenue. Revenue from the Hawaii Gas business is generated from the distribution and sales of synthetic natural gas (SNG), liquefied petroleum gas (LPG) and liquefied natural gas (LNG). Revenue is primarily a function of the volume of SNG, LPG and LNG consumed by customers and the price per thermal unit or gallon charged to customers. Because both SNG and LPG are derived from petroleum, revenue levels, without organic growth, will generally track global oil prices. All of the MIC business segments are managed separately and management has chosen to organize the Company around the distinct products and services offered. Selected information by segment is presented in the following tables. Revenue from external customers for the Company’s consolidated reportable segments were ($ in thousands): Year Ended December 31, 2016 IMTT Atlantic Contracted MIC Intersegment Total Service revenue $ 532,472 $ 740,209 $ — $ 20,762 $ (4,881 ) $ 1,288,562 Product revenue — — 150,010 213,159 — 363,169 Total revenues $ 532,472 $ 740,209 $ 150,010 $ 233,921 $ (4,881 ) $ 1,651,731 Year Ended December 31, 2015 IMTT Atlantic Contracted MIC Total Service revenue $ 550,041 $ 738,460 $ — $ — $ 1,288,501 Product revenue — — 123,797 226,952 350,749 Total revenues $ 550,041 $ 738,460 $ 123,797 $ 226,952 $ 1,639,250 Year Ended December 31, 2014 IMTT (1) Atlantic Contracted MIC Total Service revenue $ 255,934 $ 779,261 $ 29,487 $ — $ 1,064,682 Product revenue — — 19,779 264,621 284,400 Financing and equipment lease income — — 1,836 — 1,836 Total revenues $ 255,934 $ 779,261 $ 51,102 $ 264,621 $ 1,350,918 (1) Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition. In accordance with FASB ASC 280, Segment Reporting the most comparable GAAP measure EBITDA excluding non-cash items for the Company’s consolidated reportable segments is shown in the tables below ($ in thousands). Allocations of corporate expenses, intercompany fees and the tax effect have been excluded as they are eliminated on consolidation. Year Ended December 31, 2016 IMTT Atlantic Contracted MIC Total Reportable Net income $ 83,142 $ 59,538 $ 14,093 $ 35,744 $ 192,517 Interest expense, net 38,752 33,961 21,286 5,559 99,558 Provision for income taxes 57,736 39,889 14,328 20,441 132,394 Depreciation 123,346 41,493 51,120 10,533 226,492 Amortization of intangibles 11,039 49,166 4,428 792 65,425 Pension expense 7,219 110 — 1,272 8,601 Other non-cash expense (income) 657 905 (7,047 ) (11,539 ) (17,024 ) EBITDA excluding non-cash items $ 321,891 $ 225,062 $ 98,208 $ 62,802 $ 707,963 Year Ended December 31, 2015 IMTT Atlantic Contracted MIC Total Reportable Net income (loss) $ 74,726 $ 22,805 $ (7,152 ) $ 23,993 $ 114,372 Interest expense, net 37,378 35,735 28,390 7,279 108,782 Provision for income taxes 51,520 16,081 4,887 14,261 86,749 Depreciation 120,950 40,249 45,490 8,554 215,243 Amortization of intangibles 11,052 86,102 3,500 781 101,435 Pension expense 6,063 112 — 1,125 7,300 Other non-cash expense (income) 378 2,533 (6,959 ) 4,090 42 EBITDA excluding non-cash items $ 302,067 $ 203,617 $ 68,156 $ 60,083 $ 633,923 Year Ended December 31, 2014 IMTT (1) Atlantic Contracted MIC Total Reportable Net income (loss) $ 34,948 $ 36,964 $ (6,242 ) $ 21,329 $ 86,999 Interest expense, net 10,864 40,618 8,606 7,091 67,179 Provision for income taxes 25,768 25,096 823 12,635 64,322 Depreciation (2) 47,475 28,264 19,132 7,945 102,816 Amortization of intangibles 5,091 35,514 843 1,247 42,695 Pension expense 3,410 114 — 624 4,148 Other non-cash expense (income) 195 1,361 (439 ) 6,085 7,202 EBITDA excluding non-cash items $ 127,751 $ 167,931 $ 22,723 $ 56,956 $ 375,361 (1) Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition. (2) Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations. Reconciliation of total reportable segments’ EBITDA excluding non-cash items to consolidated net income (loss) before income taxes were ($ in thousands): Year Ended December 31, 2016 2015 2014 Total reportable segments EBITDA excluding non-cash items (1) $ 707,963 $ 633,923 $ 375,361 Interest income 132 55 112 Interest expense (116,933 ) (123,079 ) (73,196 ) Depreciation (2) (226,492 ) (215,243 ) (102,816 ) Amortization of intangibles (65,425 ) (101,435 ) (42,695 ) Selling, general and administrative expenses – Corporate and Other (13,056 ) (11,575 ) (15,526 ) Fees to Manager – related party (68,486 ) (354,959 ) (168,182 ) Gain from acquisition/divestiture of businesses — — 1,027,054 Equity in earnings and amortization charges of investee (1) — — 26,391 Pension expense (8,601 ) (7,300 ) (4,148 ) Other income (expense), net 17,024 645 (7,446 ) Total consolidated net income (loss) before income taxes $ 226,126 $ (178,968 ) $ 1,014,909 (1) Subsequent to July 16, 2014, the date of the IMTT Acquisition, total reportable segments' EBITDA excluding non-cash items includes the results of IMTT’s EBITDA excluding non-cash items. Prior to July 16, 2014, MIC accounted for its 50% investment in IMTT under the equity method of accounting. As such, MIC’s 50% share of IMTT’s net income was reported in equity in earnings and amortization charges of investee in the above table for the period prior to July 16, 2014. (2) Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations. Capital expenditures, on a cash basis, for the Company’s reportable segments were ($ in thousands): Year Ended December 31, 2016 2015 2014 IMTT $ 96,865 $ 96,990 $ 47,376 Atlantic Aviation 113,092 64,385 43,691 Contracted Power 69,268 15,636 14,376 MIC Hawaii 35,459 17,137 18,503 Total $ 314,684 $ 194,148 $ 123,946 Property, equipment, land and leasehold improvements, net, goodwill and total assets for the Company’s reportable segments and its reconciliation to consolidated total assets as of December 31 st Property, Equipment, Goodwill Total Assets 2016 2015 2016 2015 2016 2015 (1) IMTT $ 2,218,256 $ 2,238,654 $ 1,411,029 $ 1,410,668 $ 3,978,379 $ 4,000,079 Atlantic Aviation 465,096 390,188 468,419 464,722 1,564,668 1,502,512 Contracted Power 1,383,289 1,274,557 21,628 21,628 1,516,602 1,411,233 MIC Hawaii 279,863 212,764 123,333 120,193 501,713 386,080 Total assets of reportable segments $ 4,346,504 $ 4,116,163 $ 2,024,409 $ 2,017,211 $ 7,561,362 $ 7,299,904 Corporate and other 32 — — — (2,109 ) 8,900 Total consolidated assets $ 4,346,536 $ 4,116,163 $ 2,024,409 $ 2,017,211 $ 7,559,253 $ 7,308,804 (1) Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	11. Related Party Transactions Management Services At December 31, 2016 and 2015, the Manager held 4,510,795 and 5,506,369 shares, respectively, of the Company. Pursuant to the terms of the Third Amended and Restated Management Services Agreement (Management Agreement), the Manager may sell these shares at any time. In November 2016 and May 2015, the Manager sold 2,870,000 shares and 1,900,000 shares, respectively, of the Company and received proceeds of $233.8 million and $160.4 million, respectively, net of underwriting fees and commissions. Under the Management Agreement, the Manager, at its option, may reinvest base management fees and performance fees, if any, in shares of the Company. Since January 1, 2014, the Company paid the Manager cash dividends on shares held for the following periods: Declared Period Covered $ per Record Date Payable Date Cash Paid February 17, 2017 Fourth quarter 2016 $ 1.31 March 3, 2017 March 8, 2017 (1) October 27, 2016 Third quarter 2016 1.29 November 10, 2016 November 15, 2016 $ 5,620 July 28, 2016 Second quarter 2016 1.25 August 11, 2016 August 16, 2016 8,743 April 28, 2016 First quarter 2016 1.20 May 12, 2016 May 17, 2016 6,981 February 18, 2016 Fourth quarter 2015 1.15 March 3, 2016 March 8, 2016 6,510 October 29, 2015 Third quarter 2015 1.13 November 13, 2015 November 18, 2015 6,052 July 30, 2015 Second quarter 2015 1.11 August 13, 2015 August 18, 2015 5,693 April 30, 2015 First quarter 2015 1.07 May 14, 2015 May 19, 2015 7,281 February 17, 2015 Fourth quarter 2014 1.02 March 2, 2015 March 5, 2015 4,905 October 27, 2014 Third quarter 2014 0.98 November 10, 2014 November 13, 2014 4,438 July 3, 2014 Second quarter 2014 0.95 August 11, 2014 August 14, 2014 3,402 April 28, 2014 First quarter 2014 0.9375 May 12, 2014 May 15, 2014 3,180 February 18, 2014 Fourth quarter 2013 0.9125 March 3, 2014 March 6, 2014 2,945 (1) The amount of dividend payable to the Manager for the fourth quarter of 2016 will be determined on March 3, 2017, the record date. Under the Management Agreement, subject to the oversight and supervision of the Company’s Board of Directors, the Manager is responsible for and oversees the management of the Company’s operating businesses. In addition, the Manager has the right to appoint the Chairman of the Board of the Company, subject to minimum equity ownership, and to assign, or second, to the Company, two of its employees to serve as chief executive officer and chief financial officer of the Company and seconds or makes other personnel available as required. In accordance with the Management Agreement, the Manager is entitled to a monthly base management fee based primarily on the Company’s market capitalization, and potentially a quarterly performance fee based on the total stockholder return relative to a U.S. utilities index. Currently, the Manager has elected to reinvest the base management fees and performance fees, if any, in additional shares. For the years ended December 31, 2016, 2015 and 2014, the Company incurred base management fees of $68.5 million, $70.6 million and $46.6 million, respectively. For the years ended December 31, 2015 and 2014, the Company incurred performance fees of $284.4 million and $121.5 million, respectively. The Company did not incur a performance fee for the year ended December 31, 2016. In all of these periods, excluding $67.8 million of the performance fee for the quarter ended June 30, 2015 and $65.0 million of the performance fee for the quarter ended September 30, 2014, the Manager elected to reinvest these fees in additional shares. The unpaid portion of the base management fees and performance fees, if any, at the end of each reporting period is included in Due to Manager-related party in the consolidated balance sheets. The following table shows the Manager’s reinvestment of its base management fees and performance fees, if any, in shares, except as noted: Period Base Management Performance Shares 2016 Activities: Fourth quarter 2016 $ 18,916 $ — 230,773 (1) Third quarter 2016 18,382 — 232,488 Second quarter 2016 16,392 — 232,835 First quarter 2016 14,796 — 234,179 2015 Activities: Fourth quarter 2015 $ 17,009 $ — 227,733 Third quarter 2015 18,118 — 226,914 Second quarter 2015 18,918 135,641 1,167,873 (2) First quarter 2015 16,545 148,728 2,068,038 2014 Activities: Fourth quarter 2014 $ 14,192 $ — 208,122 Third quarter 2014 13,915 116,586 947,583 (3) Second quarter 2014 9,535 4,960 243,329 First quarter 2014 8,994 — 164,546 (1) The Manager elected to reinvest all of the monthly base management fees for the fourth quarter of 2016 in shares. The Company issued 230,773 shares for the quarter ended December 31, 2016, including 76,914 shares that were issued in January 2017 for the December 2016 monthly base management fee. (2) In July 2015, the Board requested, and the Manager agreed, that $67.8 million of the performance fee for the quarter ended June 30, 2015 be settled in cash in July 2015 to minimize dilution. The remaining $67.8 million obligation was settled and reinvested in 944,046 shares by the Manager on August 1, 2016 using the June 2016 volume weighted average share price of $71.84. (3) In October 2014, the Board requested, and the Manager agreed, that $65.0 million of the performance fee for the quarter ended September 30, 2014 be settled in cash using the proceeds from the sale of the district energy business to minimize dilution. The remainder of the fee of $51.6 million was reinvested in additional shares of MIC. The Manager is not entitled to any other compensation and all costs incurred by the Manager, including compensation of seconded staff, are paid by the Manager out of its base management fee. However, the Company is responsible for other direct costs including, but not limited to, expenses incurred in the administration or management of the Company and its subsidiaries, income taxes, audit and legal fees, acquisitions and dispositions and its compliance with applicable laws and regulations. During the years ended December 31, 2016, 2015 and 2014, the Manager charged the Company $714,000, $533,000 and $571,000, respectively, for reimbursement of out-of-pocket expenses. The unpaid portion of the out-of-pocket expenses at the end of the reporting period is included in Due to Manager-related party in the consolidated balance sheets. Third Amended and Restated Management Service Agreement On May 21, 2015, to give effect to the Conversion, Macquarie Infrastructure Corporation entered into a Third Amended and Restated Management Services Agreement, among the Company, MIC Ohana Corporation and the Manager. Concurrently with the Conversion, the Manager was issued 100 shares of a new series of special stock of the Company in order to induce the Manager to enter into the Third Amended Agreement. The sole purpose for the issuance of shares of special stock to the Manager was to preserve the Manager’s existing right to appoint one director who served as the chairman of the board of directors of MIC pursuant to the terms of MIC’s operating agreement, which right would otherwise have been lost upon consummation of the Conversion. Following the Conversion and the issuance of special stock, the Manager’s right to elect one director who serves as chairman remains the same as was in effect prior to the Conversion. The Company did not grant any additional rights to the Manager through the special stock issuance. On May 21, 2015, the Company entered into an amended and restated registration rights agreement with the Manager to give effect to the Conversion. Other Services The Company uses the resources of the Macquarie Group with respect to a range of advisory, procurement, insurance, hedging, lending and other services. Engagements involving members of the Macquarie Group are reviewed and approved by the Audit Committee of the Company’s Board of Directors. Macquarie Group affiliates are engaged on an arm’s length basis and frequently as a member of syndicate of providers whose other members establish the terms of the interaction. Advisory Services The Macquarie Group, and wholly-owned subsidiaries within the Macquarie Group, including Macquarie Bank Limited (MBL) and Macquarie Capital (USA) Inc. (MCUSA) have provided various advisory and other services and incurred expenses in connection with the Company’s equity raising activities, acquisitions and debt structuring for the Company and its businesses. Underwriting fees are recorded in stockholders’ equity as a direct cost of equity offerings. Advisory fees and out-of-pocket expenses relating to acquisitions are expensed as incurred. Debt arranging fees are deferred and amortized over the term of the credit facility. In October 2016 and July 2014, the Company completed underwritten public offerings of $402.5 million and $350.0 million, respectively, of aggregate principal amount of convertible senior notes. MCUSA served as an underwriter in these offerings and received $403,000 and $1.1 million, respectively, from the Company for such services. On June 24, 2015, the Company commenced the ATM program where the Company may offer and sell shares of its common stock, par value $0.001 per share, from time to time having an aggregate gross offering price of up to $400.0 million. These sales, if any, will be made pursuant to the terms of an equity distribution agreement entered into between the Company and the sales agents, with MCUSA being one of the sales agents. Under the terms of the equity distribution agreement, the Company may also sell shares to any sales agent as principal for its own account at a price agreed upon at the time of the sale. For the years ended December 31, 2016 and 2015, the Company did not engage MCUSA for such activities. In March 2015 and July 2014, the Company completed underwritten public offerings of 6,109,375 shares and 11,500,000 shares, respectively. MCUSA served as a joint book-running manager and an underwriter in these offerings and received $2.3 million and $3.0 million, respectively, from the Company for such services. The district energy business’ credit facility was scheduled to mature in September 2014. The Company engaged MCUSA to assist in identifying and analyzing various alternatives for paying these obligations prior to maturity and obtaining other credit facilities. In August 2014, the Company paid $1.6 million to MCUSA for such services upon closing of the sale of district energy business. On January 22, 2014, Atlantic Aviation entered into an incremental $100.0 million term loan facility, which was refinanced in October 2016. The Company engaged MCUSA as Joint Bookrunner and paid $16,000 in fees during January 2014. Long-Term Debt and Derivatives Atlantic Aviation’s $70.0 million revolving credit facility was provided by various financial institutions, including MBL which provided $15.7 million. At December 31, 2015, the revolving credit facility remained undrawn. For the years ended December 31, 2016, 2015 and 2014, Atlantic Aviation incurred and paid $90,000, $114,000 and $107,000, respectively, in interest expense related to MBL’s portion of the revolving credit facility. In October 2016, the revolving credit facility was terminated in conjunction with the completion of the refinancing of Atlantic Aviation’s new credit facility. In July 2014, the Company entered into a credit agreement at the holding company that provides a five-year, $250.0 million senior secured first lien revolving credit facility, of which $50.0 million is committed by MIHI LLC. Upon closing, the Company paid MIHI LLC $250,000 in fees. As discussed in Note 7, “Long-Term Debt”, the Company increased the aggregate commitments under its revolving credit facility from $250.0 million to $410.0 million with all terms remaining the same during the year ended December 31, 2015. MIHI LLC’s commitment of $50.0 million remained unchanged. For the years ended December 31, 2016, 2015 and 2014, the Company incurred $236,000, $237,000 and $65,000, respectively, in interest expense related to MIHI LLC’s portion of the MIC senior secured revolving credit facility. On April 1, 2015, in conjunction with the acquisition of BEC, the Company assumed the existing revolving credit facility, of which $7.5 million was committed by MIHI LLC. The Company also assumed interest rate swap contracts of which MBL was one of its counterparties. During the year ended December 31, 2015, the Company incurred and paid $8,000 in interest expense related to MIHI LLC’s portion of the revolving credit facility and paid $396,000 to MBL for interest expense in connection with the interest rate swap settlements. In connection with the repayment of the outstanding balance on BEC’s debt facilities, the Company paid $4.8 million in interest rate swap breakage fees associated with the termination of out-of-the money interest rate swap contracts to MBL. Other Transactions During 2015, Hawaii Gas appointed an independent director who is the chief executive officer of one of the lenders in the syndicate responsible for its $80.0 million term loan facility and its $60.0 million revolving credit facility, which were refinanced in February 2016. Of the $80.0 million term loan facility and the $60.0 million revolving credit facility, the portion committed by this lender changed from the original $11.4 million and $8.6 million, respectively, to $8.6 million and $6.4 million, respectively. For the years ended December 31, 2016 and 2015, the business incurred $222,000 and $156,000, respectively, in interest expense related to these facilities. In addition, Hawaii Gas held $100,000 in cash with this bank at December 31, 2016 and 2015. Macquarie Energy North America Trading, Inc. (MENAT), an indirect subsidiary of Macquarie Group Limited, entered into contracts with IMTT to lease a total of 154,000 barrels of capacity during the quarter ended June 30, 2015, of which the contract for 56,000 barrels expired within the same quarter. During the year ended December 31, 2016, MENAT entered into additional contracts with IMTT to lease an additional 1.0 million barrels of capacity, of which the contract for 823,000 barrels expired during the year. At December 31, 2016, 298,000 barrels were leased to MENAT. The revenue recognized pursuant to these agreements during the years ended December 31, 2016 and 2015 were $3.9 million and $565,000, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes The Company and its subsidiaries are subject to income taxes. The Company files a consolidated U.S. income tax return with its wholly-owned subsidiaries, including its allocated share of the taxable income from the solar and wind facilities. The Company and its subsidiaries file separate and combined state income tax returns. IMTT filed a short period consolidated federal income tax return for the period ended July 15, 2014. On July 16, 2014, the Company acquired the remaining 50% interest in IMTT and IMTT became part of the Company’s consolidated federal return group. As such, any taxable income earned by IMTT is eligible to be offset with the application of MIC net operating loss (NOL) carryforwards, and any losses by IMTT will be added to MIC’s NOL carryforwards. Prior to the IMTT Acquisition, the Company included in its income the taxable portion of distributions received from its interests in IMTT. The taxable portion of these distributions generally qualified for the 80% dividends received deduction. Components of the Company’s income tax provision (benefit) related to the income (loss) for the years ended December 31, 2016, 2015 and 2014 were ($ in thousands): Year Ended December 31, 2016 2015 2014 Current taxes: Federal $ — $ (6,884 ) $ 463 State 7,310 457 2,134 Total current tax provision (benefit) $ 7,310 $ (6,427 ) $ 2,597 Deferred taxes: Federal $ 79,796 $ (46,744 ) $ (23,339 ) State (1,185 ) (14,348 ) (1,435 ) Total deferred tax provision (benefit) 78,611 (61,092 ) (24,774 ) Change in valuation allowance (14,664 ) 2,358 (2,197 ) Total tax provision (benefit) $ 71,257 $ (65,161 ) $ (24,374 ) The Protecting Americans from Tax Hikes Act (PATH Act) retroactively extends several tax provisions applicable to corporations, including the extension of 50% bonus depreciation for certain assets placed in service in 2015, 2016 and 2017, 40% bonus depreciation for eligible property placed in service in 2018 and 30% bonus depreciation for eligible property placed in service in 2019. Other than the extension of the bonus depreciation provision, the Company does not expect the provisions of the PATH Act to have a material effect on its tax profile. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2016 and 2015, were ($ in thousands): At December 31, 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 186,948 $ 189,060 Deferred revenue 8,681 9,383 Accrued compensation 13,894 13,837 Accrued expenses 32,114 30,133 Unrealized losses on derivative instruments, net — 6,482 Other 5,942 5,496 Total gross deferred tax assets 247,579 254,391 Less: valuation allowance (4,319 ) (18,983 ) Net deferred tax assets $ 243,260 $ 235,408 Deferred tax liabilities: Intangible assets $ (145,199 ) $ (140,128 ) Investment basis difference (75,105 ) (32,816 ) Property and equipment (892,382 ) (877,065 ) Unrealized gains on derivative instruments, net (14,104 ) — Equity component convertible senior notes (11,882 ) — Prepaid expenses (704 ) (2,235 ) Total deferred tax liabilities (1,139,376 ) (1,052,244 ) Net deferred tax liabilities $ (896,116 ) $ (816,836 ) At December 31, 2016, the Company and its wholly owned subsidiaries had federal income tax NOL carryforwards of $398.1 million, which are available to offset future taxable income, if any, through 2035. The Company’s NOL balance begins to expire in 2028. Approximately $28.0 million of these NOLs may be limited, on an annual basis, due to the change of control for tax purposes of the respective subsidiaries in which such losses were incurred. The Company generated federal consolidated taxable income for the year ended December 31, 2016, which decreased the NOL carryforward. The Company believes that it will be able to utilize all federal prior year NOLs. In addition, the Company and its subsidiaries have state NOL carryforwards. State NOL carryforwards are specific to the state in which the NOL was generated and various states impose limitations on the utilization of NOL carryforwards. In assessing the need for a valuation allowance, management considers whether it is more likely than not that some portion of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. For the year ended December 31, 2016, the Company’s reduced the valuation allowance by $14.7 million primarily related to the change in New York State tax law regarding consolidated filing requirements, as the Company expects to utilize these state level NOLs. As of December 31, 2016, the Company had $896.1 million in noncurrent deferred tax liabilities. A significant portion of the Company’s deferred tax liabilities relates to tax basis temporary differences of both property and equipment and intangible assets. The Company records the acquisitions of consolidated businesses under the purchase method of accounting and accordingly recognizes a significant increase to the value of the property and equipment and to intangible assets. For tax purposes, the Company may assume the existing tax basis of the acquired businesses, in which case the Company records a deferred tax liability to reflect the increase in the purchase accounting basis of the assets acquired over the carryover income tax basis. This liability will reduce in future periods as these temporary differences reverse. For the year ended December 31, 2016, the Company recorded an income tax provision of $71.3 million compared with an income tax benefit of $65.2 million and $24.4 million for the years ended December 31, 2015 and 2014, respectively. These amounts are different from the amounts computed by applying the U.S. federal income tax rate of 35% to pretax income as a result of the following ($ in thousands): Year Ended December 31, 2016 2015 2014 Tax provision (benefit) at U.S. statutory rate $ 79,144 $ (62,639 ) $ 355,218 Permanent differences and other (1,924 ) 1,299 3,418 State income taxes, net of federal benefit 8,958 (10,082 ) (2,111 ) Income attributable to noncontrolling interest (257 ) 3,903 2,328 Gain from acquisition/divestiture of businesses — — (347,772 ) Tax effect of federal dividends received deduction — — (8,029 ) Basis adjustment for equity method investment — — (25,229 ) Change in valuation allowance (14,664 ) 2,358 (2,197 ) Total tax provision (benefit) $ 71,257 $ (65,161 ) $ (24,374 ) Uncertain Tax Positions The amount of unrecognized tax benefits at December 31, 2016 and 2015 are not significant. The Company does not expect that the amount of unrecognized tax benefits will change in the next 12 months. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense in the statements of operations, which is consistent with the recognition of these items in prior reporting periods. The federal statute of limitations on the assessment of additional income tax liabilities has lapsed for all returns filed for years ended on or before December 31, 2012. The consolidated federal income tax return for the year ended December 31, 2013 is currently under examination. Management believes the result of this examination will not have a material impact on the Company’s NOL carryforwards. The various state statutes of limitations on the assessment of additional income taxes have lapsed on all returns filed for the years ended on or before December 31, 2011.

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases	13. Leases The Company leases land, buildings, office space and certain office equipment under non-cancellable operating lease agreements that expire through January 2063. 2017 $ 47,460 2018 45,714 2019 42,923 2020 41,328 2021 40,290 Thereafter 478,087 Total $ 695,802 Rent expense under all operating leases was $53.0 million for both the years ended December 31, 2016 and 2015 and $38.5 million for the year ended December 31, 2014.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Pension and Other Postretirement Benefit Contributions [Abstract]
Employee Benefit Plans	14. Employee Benefit Plans 401(k) Savings Plan IMTT, Atlantic Aviation and the Hawaii Gas business each have a defined contribution plan under Section 401(k) of the Internal Revenue Code, allowing eligible employees to contribute a percentage of their annual compensation up to an annual amount as set by the IRS. The employer contribution to these plans ranges from 0% to 6% of eligible compensation. Employer contributions were $2.5 million for both the years ended December 31, 2016 and 2015 and $2.1 million for the year ended December 31, 2014. IMTT DB Plan Except for a plan covering certain employees covered by a collective-bargaining agreement at certain terminals, substantially all employees of IMTT are eligible to participate in a defined benefit pension plan (IMTT DB Plan). Benefits under the IMTT DB Plan are based on years of service and the employees’ highest average compensation for a consecutive five year period. IMTT’s contributions to the plan are based on the recommendations of its consulting actuary. Hawaii Gas Union Pension Plan Hawaii Gas has a defined benefit pension plan for Classified Employees of GASCO, Inc. (HG DB Plan) that accrues benefits pursuant to the terms of a collective-bargaining agreement. The plan was frozen to new participants in 2008 in connection with an agreement to increase participant benefits over a three year period after which there will be no further increases to the flat rate as described herein. The HG DB Plan is non-contributory and covers all bargaining unit employees who have met certain service and age requirements. The benefits are based on a flat rate per year of service through the date of employment termination or retirement. Future contributions will be made to meet ERISA funding requirements. The HG DB Plan’s trustee handles the plan assets and, as an investment manager, invests them in a diversified portfolio of primarily equity and fixed-income securities. Other Plan Benefits IMTT, MIC Hawaii and Atlantic Aviation have other insignificant plans that are comprised of the following. These plans are shown below collectively as “Other Plan Benefits”. IMTT IMTT is the sponsor of a defined benefit plan covering union employees at certain terminals (IMTT Union Plan). Monthly benefits under this plan are computed based on a benefit rate in effect at the date of the participant’s termination multiplied by the number of years of service. IMTT’s contributions to the plan are based on the recommendations of its consulting actuary. IMTT provides post-retirement life insurance (coverage equal to 25% of final year compensation not to exceed $25,000) and health benefits (coverage for early retirees at least 62 years old on early retirement to age 65, reimbursement of Medicare premiums for the Bayonne terminal employees and some smaller health benefits no longer offered) to retired employees. Hawaii Gas Business Hawaii Gas has a postretirement plan. The GASCO, Inc. Hourly Postretirement Medical and Life Insurance Plan (the PMLI Plan) covers all bargaining unit participants who were employed by Hawaii Gas on April 30, 1999 and who retire after the attainment of age 62 with 15 years of service. Under the provisions of the PMLI Plan, Hawaii Gas pays for medical premiums of the retirees and spouses through the age of 64. After age 64, Hawaii Gas pays for medical premiums up to a maximum of $150 per month. The retirees are also provided $1,000 of life insurance benefits. Hawaii Gas also has a retiree life insurance program for certain nonunion retirees. This plan is closed to future participants. Atlantic Aviation Atlantic Aviation sponsors a retiree medical and life insurance plan available to certain employees. Currently, the plan is funded as required to pay benefits and the plan has no assets. The Company accounts for postretirement healthcare and life insurance benefits in accordance with ASC 715, Compensation — Retirement Benefits Additional information about the fair value of the benefit plan assets, the components of net periodic cost and the projected benefit obligation as of and for the years ended December 31, 2016 and 2015 are ($ in thousands). HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Change in benefit obligation: Benefit obligation – beginning of year $ 50,044 $ 52,266 $ 136,072 $ 142,397 $ 21,912 $ 22,737 $ 208,028 $ 217,400 Service cost 744 841 6,285 6,853 810 911 7,839 8,605 Interest cost 2,046 1,988 6,172 5,914 974 912 9,192 8,814 Plan amendments — — — — — (110 ) — (110 ) Participant contributions — — — — 53 126 53 126 Actuarial losses (gains) 423 (2,752 ) 6,927 (13,236 ) 4,476 (1,498 ) 11,826 (17,486 ) Benefits paid (2,324 ) (2,299 ) (5,826 ) (5,856 ) (1,417 ) (1,166 ) (9,567 ) (9,321 ) Liability (gain)/loss due to curtailment — — (8,777 ) — — — (8,777 ) — Benefit obligation – end of year $ 50,933 $ 50,044 $ 140,853 $ 136,072 $ 26,808 $ 21,912 $ 218,594 $ 208,028 Change in plan assets: Fair value of plan assets – beginning of year $ 42,825 $ 45,475 $ 96,891 $ 103,090 $ 8,161 $ 8,468 $ 147,877 $ 157,033 Actual return on plan assets 2,716 (351 ) 4,873 (343 ) 433 (78 ) 8,022 (772 ) Employer contributions 3,500 — — — 1,141 811 4,641 811 Participant contributions — — — — 53 126 53 126 Benefits paid (2,324 ) (2,299 ) (5,826 ) (5,856 ) (1,417 ) (1,166 ) (9,567 ) (9,321 ) Fair value of plan assets – end of year $ 46,717 $ 42,825 $ 95,938 $ 96,891 $ 8,371 $ 8,161 $ 151,026 $ 147,877 During the year ended December 31, 2016, Hawaii Gas made a $3.5 million voluntary contribution to the HG DB Plan. The business is not expected to make contributions in 2017, but is projected to make a contribution less than $30,000 in 2018. During the third quarter of 2014, IMTT made a voluntary contribution payment of $20.0 million to the IMTT DB Plan and the IMTT Union Plan. The business did not make any contributions to these plans during the year ended December 31, 2016 and is not expected to make contributions through 2019. The annual amount of contributions will be dependent upon a number of factors such as market conditions and changes to regulations. The funded status at December 31, 2016 and 2015, are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Funded status Funded status at end of year $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) Net amount recognized in balance sheet (1) $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) Amounts recognized in balance sheet consisting of: Noncurrent assets $ — $ — $ — $ — $ — $ 222 $ — $ 222 Current liabilities — — — — (1,160 ) (916 ) (1,160 ) (916 ) Noncurrent liabilities (4,216 ) (7,219 ) (44,915 ) (39,181 ) (17,277 ) (13,057 ) (66,408 ) (59,457 ) Net amount recognized in balance sheet (1) $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) (1) Generally accepted accounting principles require measurement of defined benefit pension liabilities utilizing current discount rates. Statutory funding formulas permit measurement of defined benefit pension liabilities utilizing discount rates based on a 25-year average of those rates, which more closely matches the expected payout period for those liabilities. The IMTT and Hawaii Gas defined benefit pension plans both exceed 100% of the statutory funding target as of December 31, 2016. Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss for the years ended December 31, 2016 and 2015 are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Prior service credit $ — $ — $ — $ — $ 95 $ 110 $ 95 $ 110 Accumulated loss (12,000 ) (12,698 ) (9,577 ) (9,926 ) (5,594 ) (1,140 ) (27,171 ) (23,764 ) Accumulated other comprehensive loss (12,000 ) (12,698 ) (9,577 ) (9,926 ) (5,499 ) (1,030 ) (27,076 ) (23,654 ) Net periodic benefit cost in excess (deficit) of cumulative employer contributions 7,784 5,479 (35,338 ) (29,255 ) (12,938 ) (12,721 ) (40,492 ) (36,497 ) Net amount recognized in balance sheet $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) The components of net periodic benefit cost and other changes in other comprehensive (income) loss for the plans are shown below ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Components of net periodic benefit cost: Service cost $ 744 $ 841 $ 716 $ 6,285 $ 6,853 $ 2,799 $ 810 $ 911 $ 409 $ 7,839 $ 8,605 $ 3,924 Interest cost 2,046 1,988 1,988 6,172 5,914 2,530 974 912 480 9,192 8,814 4,998 Expected return on plan assets (2,448 ) (2,670 ) (2,268 ) (6,374 ) (7,020 ) (3,049 ) (502 ) (585 ) (183 ) (9,324 ) (10,275 ) (5,500 ) Recognized actuarial loss (gain) 854 883 122 — (534 ) 579 91 (31 ) 200 945 318 901 Amortization of prior service (cost) credit — — — — (78 ) 78 (15 ) (5 ) 5 (15 ) (83 ) 83 Net periodic benefit cost $ 1,196 $ 1,042 $ 558 $ 6,083 $ 5,135 $ 2,937 $ 1,358 $ 1,202 $ 911 $ 8,637 $ 7,379 $ 4,406 Other changes recognized in other comprehensive (income) loss: Prior service credit arising during the year $ — $ — $ — $ — $ — $ — $ — $ (110 ) $ — $ — $ (110 ) $ — Net loss (gain) arising during the year 156 268 7,925 8,428 (5,873 ) 15,844 4,545 (836 ) 1,406 13,129 (6,441 ) 25,175 Liability gain due to curtailment — — — (8,777 ) — — — — — (8,777 ) — — Amortization of prior service cost (credit) — — — — 78 (78 ) 15 5 (5 ) 15 83 (83 ) Amortization of (loss) (854 ) (883 ) (122 ) — 534 (579 ) (91 ) 31 (200 ) (945 ) (318 ) (901 ) Total recognized in other comprehensive (income) loss $ (698 ) $ (615 ) $ 7,803 $ (349 ) $ (5,261 ) $ 15,187 $ 4,469 $ (910 ) $ 1,201 $ 3,422 $ (6,786 ) $ 24,191 The estimated amounts that will be amortized from accumulated other comprehensive (income) loss over the next year are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Amortization of prior service cost (credit) $ — $ — $ — $ — $ (15 ) $ (15 ) $ (15 ) $ (15 ) Amortization of net loss 794 854 — — 264 76 1,058 930 The assumptions used in accounting for the HG DB Plan Benefits, IMTT DB Plan Benefits and Other Plan Benefits are: HG DB Plan Benefits IMTT DB Plan Benefits Other Plan Benefits 2016 2015 2014 2016 2015 2014 2016 2015 2014 Weighted average assumptions to determine benefit obligations: Discount rate 4.00% 4.20% 3.90% 4.30% 4.65% 4.25% 3.56% to 4.25% 3.78% to 4.55% 3.45% to 4.15% Rate of compensation increase N/A N/A N/A 4.57% 4.57% 4.57% 4.57% (1) 4.57% (1) 4.57% (1) Measurement date December 31 December 31 December 31 December 31 December 31 December 31 December 31 December 31 December 31 Weighted average assumptions to determine net cost: Discount rate 4.20% 3.90% 4.70% 4.65% 4.25% 4.55% 3.78% to 4.55% 3.45% to 4.15% 4.20% to 4.45% Expected long-term rate of return on plan assets during fiscal year 5.90% 5.90% 5.90% 6.75% 7.00% 7.00% 6.25% (2) 7.00% (2) 7.00% (2) Rate of compensation increase N/A N/A N/A 4.57% 4.57% 4.57% 4.57% (1) 4.57% (1) 4.57% (1) Assumed healthcare cost trend rates: Initial health care cost trend rate 7.20% to 7.25% 7.50% 7.75% to 7.80% Ultimate rate 4.50% to 5.00% 4.50% to 5.00% 4.50% to 5.00% Year ultimate rate is reached 2025 to 2028 2025 to 2028 2025 to 2028 (1) Only applies to IMTT post-retirement life insurance plan. (2) Only applies to IMTT Union Plan. Pension asset investment decisions are made with assistance of an outside paid advisor to achieve the multiple goals of high rate of return, diversification and safety. The business has instructed the trustee, the investment manager, to maintain the allocation of the defined benefit plans’ assets between equity mutual fund securities, fixed income mutual fund securities, mixed equity and fixed income mutual fund securities, money market funds and cash within the pre-approved parameters set by the management. The weighted average asset allocation at December 31, 2016 and 2015 was: HG DB IMTT DB Other 2016 2015 2016 2015 2016 2015 Equity securities 56 % 60 % 51 % 58 % 51 % 58 % Fixed income securities 27 % 30 % 44 % 37 % 48 % 41 % Mixed income securities 7 % 8 % — — — — Private equity — — 4 % 3 % — — Cash 10 % 2 % 1 % 2 % 1 % 1 % Total 100 % 100 % 100 % 100 % 100 % 100 % The expected returns on plan assets were estimated based on the allocation of assets and management’s expectations regarding future performance of the investments held in the investment portfolios. The asset allocations as of December 31, 2016 and 2015 measurement dates were ($ in thousands): Fair Value Measurements at December 31, 2016 Total Quoted Prices Significant Significant Asset category: Cash and money market $ 5,890 $ 5,890 $ — $ — Equity securities: Domestic equities 63,552 63,552 — — International equities 15,727 15,727 — — Fixed income securities: Domestic fixed income 59,028 59,028 — — Domestic mixed income securities 3,401 3,401 — — Domestic private equity 3,428 — — 3,428 Total $ 151,026 $ 147,598 $ — $ 3,428 Fair Value Measurements at December 31, 2015 Total Quoted Prices Significant Significant Asset category: Cash and money market $ 3,138 $ 3,138 $ — $ — Equity securities: Domestic equities 66,290 66,290 — — International equities 20,473 20,473 — — Fixed income securities: Domestic fixed income 50,860 50,860 — — International fixed income 1,035 1,035 — — Domestic mixed income securities 3,401 3,401 — — Domestic private equity 2,680 — — 2,680 Total $ 147,877 $ 145,197 $ — $ 2,680 The estimated future benefit payments for the next ten years are ($ in thousands): HG DB Plan IMTT DB Plan Benefits Other Total 2017 $ 2,742 $ 7,363 $ 1,447 $ 11,552 2018 2,869 5,716 1,523 10,108 2019 2,933 6,529 1,618 11,080 2020 3,003 7,813 1,803 12,619 2021 3,064 7,103 1,779 11,946 Thereafter 15,520 41,805 8,882 66,207 Total $ 30,131 $ 76,329 $ 17,052 $ 123,512

Legal Proceedings and Contingen

Legal Proceedings and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings and Contingencies	15. Legal Proceedings and Contingencies The Company and its subsidiaries are subject to legal proceedings arising in the ordinary course of business. In management’s opinion, the Company has adequate legal defenses and/or insurance coverage with respect to the eventuality of such actions, and does not believe the outcome of any pending legal proceedings will be material to the Company’s financial position or result of operations. IMTT Bayonne — Remediation Estimate The Bayonne, New Jersey terminal, portions of which have been acquired and aggregated over a 30-year period, contain pervasive remediation requirements that were assumed at the time of purchase from the various former owners. One former owner retained environmental remediation responsibilities for a purchased site as well as sharing other remediation costs. These remediation requirements are documented in two memoranda of agreement and an administrative consent order with the State of New Jersey. Remediation efforts entail removal of free product, soil treatment, repair/replacement of sewer systems, and the implementation of containment and monitoring systems. These remediation activities are estimated to span a period of ten to twenty or more years at a cost ranging from $30.0 million to $65.0 million. The remediation activities at the terminal are estimated based on currently available information, in undiscounted U.S. dollars and is inherently subject to relatively large fluctuation. Except as noted above, there are no material legal proceedings pending other than ordinary routine litigation incidental to the Company’s businesses.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	16. Subsequent Events Dividend On February 17, 2017, the Board of Directors declared a dividend of $1.31 per share for the quarter ended December 31, 2016, which is expected to be paid on March 8, 2017 to holders of record on March 3, 2017.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (Unaudited)	17. Quarterly Data (Unaudited) Quarter ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2016 Revenue $ 396,387 $ 397,579 $ 420,524 $ 437,241 Operating income 88,776 76,507 75,658 80,200 Net income attributable to MIC 22,355 19,192 42,026 72,808 Per share information attributable to MIC: Net income per share – basic $ 0.28 $ 0.24 $ 0.52 $ 0.89 Net income per share – diluted (1) 0.28 0.24 0.51 0.79 Cash dividends declared per share $ 1.20 $ 1.25 $ 1.29 $ 1.31 2015 Revenue $ 398,498 $ 423,689 $ 415,709 $ 401,354 Operating (loss) income (115,365 ) (75,301 ) 73,449 59,985 Net (loss) income attributable to MIC (89,002 ) (63,096 ) 10,638 32,923 Per share information attributable to MIC: Net (loss) income per share – basic $ (1.22 ) $ (0.80 ) $ 0.13 $ 0.41 Net (loss) income per share – diluted (1) (1.22 ) (0.80 ) 0.13 0.41 Cash dividends declared per share $ 1.07 $ 1.11 $ 1.13 $ 1.15 (1) Diluted net income (loss) per share reflects the effect of potentially dilutive shares assuming: (i) the restricted stock unit grants provided to the independent directors had been fully converted to shares on the grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued in July 2014 and October 2016 had been fully converted into shares on the issue date. The potentially dilutive shares are excluded in the calculation if the effect is anti-dilutive or when the Company has a net loss for the period.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company consolidates investments where it has a controlling financial interest. The general condition for a controlling financial interest is ownership of a majority of the voting interest and, therefore, as a general rule, ownership, directly or indirectly, of over 50% of the outstanding voting shares is a condition for consolidation. In addition, if the Company demonstrates that it has the ability to direct policies and management, this may be also indication for consolidation. For investments in variable interest entities, the Company consolidates when it is determined to be the primary beneficiary of the variable interest entity. As of December 31, 2016, the Company was the primary beneficiary in seven solar facilities and two wind facilities in the U.S. and consolidated these projects accordingly.
Investments	Investments The Company accounts for 50% or less owned companies over which it has the ability to exercise significant influence using the equity method of accounting, otherwise the cost method is used. The Company’s share of net income or losses of equity investments is included in equity in earnings and amortization charges of investee in the consolidated statements of operations. Losses are recognized in other income (expense), net when a decline in the value of the investment is deemed to be other than temporary. In making this determination, the Company considers factors to be evaluated in determining whether a loss in value should be recognized, including the Company’s ability to hold its investment and inability of the investee to sustain an earnings capacity, which would justify the carrying amount of the investment. Subsequent to the IMTT Acquisition on July 16, 2014, the Company does not have any investments accounted for under the equity method of accounting on its consolidated balance sheet. From January 1, 2014 through July 15, 2014, the results of IMTT were accounted for under the equity method of accounting. From July 16, 2014 through December 31, 2014 and subsequent periods, the Company has consolidated the financial results of IMTT. Investment in unconsolidated business of $8.8 million and $8.3 million at December 31, 2016 and 2015, respectively, represent primarily a 20% ownership interest in a joint venture acquired in conjunction with the IMTT Acquisition on July 16, 2014. This investment is accounted for at cost on the consolidated balance sheet. Income from this investment is recorded in other income (expense), net, on the consolidated statements of operations.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements, which are in conformity with generally accepted accounting principles (GAAP) requires the Company to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. The Company evaluates these estimates and judgments on an ongoing basis and the estimates are based on experience, current and expected future conditions, third-party evaluations and various other assumptions that the Company believes are reasonable under the circumstances. Significant items subject to such estimates and assumptions include the carrying amount of property, equipment, land and leasehold improvements, intangibles and goodwill; assets and obligations related to employee benefits; and valuation of derivative instruments. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from the estimates and assumptions used in the financial statements and related notes.
Business Combinations	Business Combinations Acquisitions of businesses that the Company controls are accounted for under the purchase method of accounting. The amounts assigned to the identifiable assets acquired and liabilities assumed in connection with acquisitions are based on estimated fair values as of the date of the acquisition, with the remainder, if any, recorded as goodwill. The fair values are determined by the Company’s management, taking into consideration information supplied by the management of acquired entities and other relevant information. Such information includes valuations supplied by independent appraisal experts for significant business combinations. The valuations are generally based upon future cash flow projections for the acquired assets, discounted to present value. The determination of fair values require significant judgment both by management and outside experts engaged to assist in this process.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments, including commercial paper issued by a counterparty with Standard & Poor rating of A1+, with a maturity of three months or less when purchased to be cash equivalents. The Company did not have any commercial paper at December 31, 2016 and 2015.
Restricted Cash	Restricted Cash Restricted cash on the consolidated balance sheets represents cash account agreements that require the businesses within the CP segment and the solar facilities in the MIC Hawaii segment that have long-term debt to maintain cash accounts restricted to fund operations, capital expenditures, debt service and make distributions to the Company and its partners. For these businesses, cash generated from operations is recorded in restricted cash upon receipt. Bayonne Energy Center (BEC), within the CP segment, also uses restricted cash to fund capital expenditures. The Company recorded $16.5 million of cash pledged as collateral in the consolidated balance sheet at December 31, 2016, of which $16.4 million was recorded within current assets. At December 31, 2015, the Company recorded $19.0 million of cash pledged as collateral in the consolidated balance sheet, of which $18.9 million was recorded within current assets. The remaining amounts are included in other noncurrent assets.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company uses estimates to determine the amount of the allowance for doubtful accounts necessary to reduce billed and unbilled accounts receivable to their net realizable value. The Company estimates the required allowance by reviewing the status of past-due receivables and analyzing historical bad debt trends. Actual collection experience has not varied significantly from estimates primarily due to credit policies and a lack of concentration of accounts receivable. The Company writes off receivables deemed to be uncollectible to the allowance for doubtful accounts.
Inventory	Inventory Inventory consists principally of fuel purchased from various third-party vendors at Atlantic Aviation and the Hawaii Gas business and materials and supplies at all of the operating businesses. Fuel inventory is stated at the lower of cost or market. Materials and supplies inventory is valued at the lower of average cost or market. Inventory sold is recorded using the first-in-first-out method at Atlantic Aviation and an average cost method at Hawaii Gas. IMTT also has inventory for sale for its spill response activity business. This is carried at lower of average cost or market. Cash flows related to the sale of inventory are classified in net cash provided by operating activities in the consolidated statements of cash flows. The Company’s inventory balance at December 31, 2016 comprised $14.3 million of inventory held for sale and $17.2 million of materials and supplies. The Company’s inventory balance at December 31, 2015 comprised $14.3 million of inventory held for sale and $15.2 million of materials and supplies.
Property, Equipment, Land and Leasehold Improvements	Property, Equipment, Land and Leasehold Improvements Property, equipment and land are initially recorded at cost. Leasehold improvements are recorded at the initial present value of the minimum lease payments less accumulated amortization. Major renewals and improvements are capitalized while maintenance and repair expenditures are expensed when incurred. Interest expense relating to construction in progress is capitalized as an additional cost of the asset. The Company depreciates property, equipment and leasehold improvements over their estimated useful lives on a straight-line basis. Within the CP segment, depreciation expense for the district energy business was included in cost of services in the consolidated statements of operations prior to the Company’s divestiture of the business on August 21, 2014. The estimated economic useful lives range according to the table below: Buildings 10 to 68 years Leasehold and land improvements 5 to 40 years Machinery and equipment 3 to 62 years Furniture and Fixtures 3 to 15 years
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill consists of costs in excess of the aggregate purchase price over the fair value of tangible and identifiable intangible net assets acquired in business combinations. The cost of intangible assets with determinable useful lives is amortized over their estimated useful lives ranging as follows: Customer relationships 5 to 30 years Contractual arrangements 5 to 57 years Non-compete agreements 3 to 10 years Leasehold rights 25 years Trade names 20 years Technology 5 years
Impairment of Long-lived Assets, Excluding Goodwill	Impairment of Long-lived Assets, Excluding Goodwill Long-lived assets, including amortizable intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable. These events or changes in circumstances may include a significant deterioration of operating results, changes in business plans, or changes in anticipated future cash flows. If an impairment indicator is present, the Company evaluates recoverability by a comparison of the carrying amount of the assets to future undiscounted net cash flows expected to be generated by the assets. If the assets are impaired, the impairment recognized is measured by the amount by which the carrying amount exceeds the fair value of the assets. Fair value is generally determined by estimates of discounted cash flows or value expected to be realized in a third party sale. The discount rate used in any estimate of discounted cash flows would be the rate required for a similar investment of like risk.
Impairment of Goodwill	Impairment of Goodwill Goodwill is tested for impairment at least annually or when there is a triggering event that indicates impairment. For the annual impairment test, the Company can make a qualitative assessment of whether it is more likely than not that a reporting unit’s fair value is less than its carrying amount before applying the two-step goodwill impairment test, as discussed below. If an entity concludes it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, it need not perform the two-step impairment test. If an entity concludes that it is more likely than not that the fair value of reporting unit is less than its carrying amount, or if there is a triggering event that indicates impairment, the Company needs to perform the two-step impairment test. This requires management to make judgments in determining what assumptions to use in the calculation. The first step is to determine the estimated fair value of each reporting unit with goodwill. The reporting units of the Company, for purposes of the impairment test, are those components of operating segments for which discrete financial information is available and segment management regularly reviews the operating results of that component. When determining reporting units, components with similar economic characteristics are combined. The Company estimates the fair value of each reporting unit by estimating the present value of the reporting unit’s future discounted cash flows or value expected to be realized in a third party sale. If the recorded net assets of the reporting unit are less than the reporting unit’s estimated fair value, then no impairment is indicated. Alternatively, if the recorded net assets of the reporting unit exceed its estimated fair value, then goodwill is assumed to be impaired and a second step is performed. In the second step, the implied fair value of goodwill is determined by deducting the estimated fair value of all tangible and identifiable intangible net assets of the reporting unit from the estimated fair value of the reporting unit. If the recorded amount of goodwill exceeds this implied fair value, an impairment charge is recorded for the excess.
Impairment of Indefinite-lived Intangibles, Excluding Goodwill	Impairment of Indefinite-lived Intangibles, Excluding Goodwill Indefinite-lived intangibles, which consist of trademarks, are considered impaired when the carrying amount of the asset exceeds its implied fair value. The Company estimates the fair value of each trademark using the relief-from-royalty method that discounts the estimated net cash flows the Company would have to pay to license the trademark under an arm’s length licensing agreement. If the recorded indefinite-lived intangible is less than its estimated fair value, then no impairment is indicated. Alternatively, if the recorded intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess.
Debt Issuance Costs	Debt Issuance Costs The Company capitalizes all direct costs incurred in connection with the issuance of debt as debt issuance costs. These costs are amortized over the contractual term of the debt instrument, which ranges from 5 to 23 years, using the effective interest method.
Derivative Instruments	Derivative Instruments From time to time the Company enters into interest rate derivative agreements to minimize potential variations in cash flows resulting from fluctuations in interest rates and their impact on its variable-rate debt. Since the fourth quarter of 2014, the Company’s Hawaii Gas business entered into commodity price hedges to mitigate the impact of fluctuations in propane prices on its cash flows. The Company accounts for derivatives and hedging activities in accordance with Accounting Standard Codification (ASC) 815 Derivatives and Hedging
Financial Instruments	Financial Instruments The Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and variable-rate senior debt, are carried at cost, which approximates their fair value because of either the short-term maturity, or competitive interest rates assigned to these financial instruments.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. The Company places its cash and cash equivalents with financial institutions and its balances may exceed federally insured limits. The Company’s accounts receivable are mainly derived from fuel and gas sales and services rendered under contract terms with commercial and private customers located primarily in the United States. At December 31, 2016 and 2015, there were no outstanding accounts receivable due from a single customer that accounted for more than 10% of the total accounts receivable. Additionally, no single customer accounted for more than 10% of the Company’s revenue during the years ended December 31, 2016, 2015 and 2014.
Foreign Currency Translation	Foreign Currency Translation The assets and liabilities of IMTT’s Newfoundland and Quebec locations are translated from their local currency (Canadian dollars) to U.S. dollars at exchange rates in effect at the end of the year and consolidated statement of operations accounts are translated at average exchange rates for the year. Translation gains or losses as a result of changes in the exchange rate are recorded as a component of other comprehensive income (loss).
Tolling Agreements Liability	Tolling Agreements Liability Tolling agreements represent agreements with an off-taker where BEC agrees to sell 62.5% of its capacity, energy and ancillary services for fixed monthly tolling and capacity payments and monthly variable operation and maintenance (O&M) fees. Fixed payments received under these contracts were below prevailing market rates at the date of acquisition. The difference between the present value of the fixed payments and the present value of the market rates at the date of acquisition is recorded as a liability on the consolidated balance sheet as part of purchase accounting. This liability is amortized into revenue over a weighted average life of the tolling agreements of approximately thirteen years with approximately eleven years remaining at December 31, 2016.
Income (Loss) per Share	Income (Loss) per Share The Company calculates income (loss) per share using the weighted average number of common shares outstanding during the period. Diluted income (loss) per share is computed using the weighted average number of dilutive common equivalent shares outstanding during the period. Common equivalent shares consist of shares issuable upon conversion of the Company’s convertible senior notes (using the if-converted method), stock units granted to the Company’s independent directors and fees payable to the Manager that will be reinvested in shares by the Manager in a future period. Common equivalent shares are excluded from the calculation if their effect is anti-dilutive.
Comprehensive Income (Loss)	Comprehensive Income (Loss) The Company follows the requirements of ASC 220 Comprehensive Income
Revenue Recognition	Revenue Recognition The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller’s price to the buyer is fixed and determinable and collectability is probable. IMTT Contracts for the use of storage capacity at the various terminals predominantly have non-cancelable terms of one to five years. These contracts generally provide for payments for providing storage capacity throughout their term based on a fixed rate per barrel of capacity leased, as adjusted annually for inflation indices. Contract revenue is recognized over the term based on the rate specified in the contract. Revenue from the rendering of ancillary services (e.g., product movement (throughput), heating, blending, etc.) is recognized as the related services are performed based on contract rates. Throughput revenues in excess of those provided by contract are not recognized until the throughput quantity specified in the contract for the applicable period is exceeded. Payments received prior to the related services being performed or as a reimbursement for specific fixed asset additions or improvements related to a customer’s contract are recorded as deferred revenue and ratably recognized as revenues over the contract term; the noncurrent portion is included in other noncurrent liabilities. Environmental response services revenues are recognized as services are rendered. Revenue from IMTT is recorded in service revenue on the consolidated statements of operations. Atlantic Aviation Revenue from Atlantic Aviation is recorded in service revenue on the consolidated statements of operations. Services provided by Atlantic Aviation include: (i) Fuel services recognized when fuel has been delivered to the customer, collection of the resulting receivable is probable, persuasive evidence of an arrangement exists and the fee is fixed or determinable. Fuel services are recorded net of volume discounts and rebates; (ii) Certain fueling fees for fueling certain carriers with fuel owned by such carriers. Revenue from these transactions are recorded based on the service fee earned and does not include the cost of the carriers’ fuel; and (iii) Other services consisting principally of de-icing services, landing and fuel distribution fees as well as rental income for hangar and terminal use. Other fixed base operation (FBO) revenue is recognized as the services are rendered to the customer. CP Bayonne Energy Center (BEC) Revenue from BEC is recorded in product revenue on the consolidated statements of operations. With respect to BEC’s contracted capacity, revenue is recognized as energy, capacity and ancillary services are sold to the off-taker under the third-party tolling agreements, which are based on a fixed rate per megawatt (MW) of capacity and not subject to dispatch or utilization. A portion of the revenues under the tolling agreements are subject to annual increases. Revenues under the tolling agreements are subject to availability of capacity (subject to a historical rolling average forced outage factor). Variable operating and major maintenance revenues under the tolling agreements are a function of net plant output and a negotiated rate, which is adjusted annually based on historical plant experience. With respect to BEC’s residual capacity, revenue is recognized as energy, capacity and ancillary services are sold into the New York Independent System Operator (NYISO) energy market, which are based on prevailing market rates at the time such services are sold. Volumes of energy and ancillary services sold are subject to BEC’s market based dispatch from NYISO. Solar and wind facilities Revenue from the solar and wind facilities are recognized when the electricity is provided to the utility companies. Owners of the solar and wind facilities sell substantially all of the electricity generated at a fixed price to electric utilities pursuant to long-term (typically 20 – 25 years) power purchase agreements (PPAs). Customers are billed on a monthly-cycle basis. Revenue from the solar and wind facilities are recorded in product revenue on the consolidated statements of operations. District energy business (through the date sold) Revenue from cooling capacity and consumption was recognized at the time of performance of service. Cash received from customers for services to be provided in the future was recorded as unearned revenue and recognized over the expected service period on a straight-line basis. Revenue from the district energy business was recorded in service revenue on the consolidated statements of operations through the date of sale on August 21, 2014. MIC Hawaii Hawaii Gas Hawaii Gas recognizes revenue when products are delivered. Sales of gas to customers are billed on a monthly-cycle basis. Earned but unbilled revenue is accrued and included in accounts receivable and revenue based on the amount of gas that is delivered but not billed to customers from the latest meter reading or billed delivery date to the end of an accounting period. The related costs are charged to expense. Most revenue is based upon consumption; however, certain revenue is based upon a flat rate .
Other Businesses	Other businesses The other businesses within MIC Hawaii consist of a mechanical contractor focused on designing and constructing energy efficient building infrastructure together with controlling interests in renewable and distributed power facilities including two facilities on Oahu. Revenue generated by the mechanical contractor business is recorded in service revenue and revenue generated by the renewable facilities are recorded in product revenue. At December 31, 2016, the signed contract backlog from the mechanical contractor business totaled approximately $75.0 million and is expected to be recognized into revenue within two to three years.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The regulated utility operations of the Hawaii Gas business are subject to regulations with respect to rates, service, maintenance of accounting records, and various other matters by the Hawaii Public Utilities Commission (HPUC). The established accounting policies recognize the financial effects of the rate-making and accounting practices and policies of the HPUC. Regulated utility operations are subject to the provisions of ASC 980, Regulated Operations ASC 980 may, at some future date, be deemed inapplicable because of changes in the regulatory and competitive environments or other factors. If the Company were to discontinue the application of this guidance, the Company would be required to write-off its regulatory assets and regulatory liabilities and would be required to adjust the carrying amount of any other assets, including property, plant and equipment, that would be deemed not recoverable related to these affected operations. The Company believes its regulated operations in the Hawaii Gas business continue to meet the criteria of ASC 980 and that the carrying value of its regulated property, plant and equipment is recoverable in accordance with established HPUC rate-making practices.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based on differences between financial reporting and tax basis of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company and its more than 80% owned subsidiaries file a consolidated U.S. federal income tax return, including its allocated share of the taxable income from its solar and wind facilities. The investments in solar and wind facilities within the CP and the MIC Hawaii segments are held in various LLCs, which are treated as partnerships for income tax purposes. Prior to the IMTT Acquisition in July 2014, the Company’s consolidated income tax return did not include IMTT and the district energy business, both of which were less than 80% owned by the Company and each filed separate income tax returns. Subsequent to the Company’s acquisition of the remaining 50% interest in IMTT, IMTT became a wholly owned subsidiary and files as part of the Company’s consolidated federal income tax return. The district energy business continued to file separate income tax returns through 2014. The Company sold its interest in the district energy business on August 21, 2014. In assessing the need for a valuation allowance, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment.
Reclassifications	Reclassifications Certain reclassifications were made to the financial statements for the prior periods to conform to current year presentation.
Recently Issued Accounting Standards	Recently Issued Accounting Standards On January 5, 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business On November 17, 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash On February 25, 2016, FASB issued ASU No. 2016-02, Leases (Topic 842) On November 20, 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes On September 25, 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement Period Adjustments In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) • ASU 2015-14 (Issued August 2015) — Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date • ASU 2016-08 (Issued March 2016) — Principal versus Agent Consideration (Reporting Revenue Gross versus Net) • ASU 2016-10 (Issued April 2016) — Identifying Performance Obligations and Licensing • ASU 2016-12 (Issued May 2016) — Narrow-Scope Improvements and Practical Expedients • ASU 2016-20 (Issued December 2016) — Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers With the deferral, the new standard is effective for the Company on January 1, 2018. Early application is permitted to the original effective date of January 1, 2017. There are two adoption methods available for implementation of the standard related to the recognition of revenue from contracts with customers. Under one method, the new guidance is applied retrospectively to contracts for each reporting period presented, subject to allowable practical expedients. Under the other method, the new guidance is applied only to the most current period presented, recognizing the cumulative effect of the change as an adjustment to the beginning balance of retained earnings, and also requires additional disclosures comparing the results to the previous guidance. The Company is currently evaluating these adoption methods, the impact that this standard will have on the Company’s financial statements, and the changes to its systems, processes and internal controls to meet the reporting and disclosure requirements. Upon initial evaluation, the Company believes key changes in the standard that impact the Company’s revenue recognition relate to the allocation of contract revenues between various services and equipment, and the timing of when those revenues are recognized. The Company is still in the process of evaluating these impacts and other areas of the standard and its effect on the Company’s financial statements and related disclosures. The Company currently includes sales, excise and value-added taxes related to sales transactions within revenue on the consolidated statements of operations. Upon adoption of ASU 2014-09, the Company will exclude sales-based taxes collected on behalf of third parties from product revenue and include these amounts in cost of services and product sales. The result will be a reclassification on the consolidated statements of operations. ASU 2014-09 also introduces new qualitative and quantitative disclosure requirements about contracts with customers including revenue and impairments recognized, disaggregation of revenue and information about contract balance and performance obligations. Information is required about significant judgments and changes in judgments in determining the timing of satisfaction of performance obligations. Additional disclosures are required about assets recognized from the costs to obtain or fulfill a contract. The Company is still in the process of evaluating what disclosures will be required, but expects the level of disclosures related to revenue recognition to increase. On July 22, 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory, On April 7, 2015, the FASB issued ASU No. 2015-03, Interest — Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs On February 18, 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis

Summary of Significant Accoun29

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of Estimated Economic Useful Lives of Property Plant and Equipment	Buildings 10 to 68 years Leasehold and land improvements 5 to 40 years Machinery and equipment 3 to 62 years Furniture and Fixtures 3 to 15 years
Schedule of Estimated Useful Lives of Intangible Assets	Customer relationships 5 to 30 years Contractual arrangements 5 to 57 years Non-compete agreements 3 to 10 years Leasehold rights 25 years Trade names 20 years Technology 5 years

Income (Loss) per Share (Tables

Income (Loss) per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Reconciliation of Earnings Income (Loss) per Share	Year Ended December 31, 2016 2015 2014 Numerator: Net income (loss) attributable to MIC $ 156,381 $ (108,537 ) $ 1,042,028 Interest expense attributable to convertible senior notes – July 2014, net of taxes (1) — — 3,016 Interest expense attributable to convertible senior notes – October 2016, net of taxes (4,523 ) — — Diluted net income (loss) attributable to MIC $ 151,858 $ (108,537 ) $ 1,045,044 Denominator: Weighted average number of shares outstanding: basic 80,892,654 77,997,826 62,990,312 Dilutive effect of restricted stock unit grants 9,589 — 12,637 Dilutive effect of fees to Manager-related party 549,404 — — Dilutive effect of convertible senior notes – July 2014 — — 1,922,616 Dilutive effect of convertible senior notes – October 2016 766,980 — — Weighted average number of shares outstanding: diluted 82,218,627 77,997,826 64,925,565 Income (loss) per share: Basic income (loss) per share attributable to MIC $ 1.93 $ (1.39 ) $ 16.54 Diluted income (loss) per share attributable to MIC $ 1.85 $ (1.39 ) $ 16.10 (1) For the year ended December 31, 2014, diluted income per share attributable to MIC does not include the after-tax impact of the write-off of deferred financing costs attributable to the July 2014 2.875% Convertible Senior Notes. If the after-tax impact of deferred financing costs were added back to net income for the year ended December 31, 2014, the diluted income per share attributable to MIC would have been $16.01.
Schedule of Antidilutive Securities	Year Ended December 31, 2016 2015 2014 Restricted stock unit grants — 9,410 — Fees to Manager – related party (1) — 449,126 — Convertible senior notes – July 2014 4,177,097 4,160,717 — Total 4,177,097 4,619,253 — (1) Represents $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016. The weighted average potentially dilutive shares of common stock in the above table include shares assumed to have been reinvested in shares by the Manager in July 2015.

Property, Equipment, Land and31

Property, Equipment, Land and Leasehold Improvements (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	As of December 31, 2016 2015 Land $ 304,240 $ 291,521 Easements 131 131 Buildings 41,711 41,049 Leasehold and land improvements 673,122 590,646 Machinery and equipment 3,764,553 3,455,776 Furniture and fixtures 35,454 29,547 Construction in progress 233,184 203,146 5,052,395 4,611,816 Less: accumulated depreciation (705,859 ) (495,653 ) Property, equipment, land and leasehold improvements, net $ 4,346,536 $ 4,116,163

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	As of December 31, 2016 2015 Contractual arrangements $ 912,728 $ 901,807 Non-compete agreements 10,014 9,665 Customer relationships 348,678 340,425 Leasehold rights 350 350 Trade names 16,091 16,091 Technology 8,760 8,760 1,296,621 1,277,098 Less: accumulated amortization (407,650 ) (342,206 ) Intangible assets, net $ 888,971 $ 934,892
Schedule of Estimated Future Amortization Expense	2017 $ 60,828 2018 56,537 2019 53,588 2020 49,439 2021 46,995 Thereafter 614,093 Total $ 881,480
Schedule of Goodwill	Goodwill acquired in business combinations, net of disposals, at $ 2,143,057 Accumulated impairment charges (123,200 ) Other (2,646 ) Balance at December 31, 2015 2,017,211 Goodwill related to 2016 acquisitions 6,837 Other 361 Balance at December 31, 2016 $ 2,024,409

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2016
Accounts Payable and Accrued Liabilities, Current [Abstract]
Schedule of Accrued Expenses	As of December 31, 2016 2015 Payroll and related liabilities $ 29,851 $ 26,740 Purchase of property and equipment 11,669 8,045 Interest 13,153 10,684 Insurance 3,957 6,361 Property tax 6,046 4,670 Other taxes (1) 4,689 5,750 Other 14,369 16,277 $ 83,734 $ 78,527 (1) Other taxes primarily consists of sales and franchise taxes.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Instrument [Line Items]
Schedule of Long-Term Debt	As of December 31, 2016 2015 IMTT $ 1,140,975 $ 1,127,223 Atlantic Aviation 449,691 604,609 CP 604,862 555,486 MIC Hawaii 200,744 180,000 MIC Corporate (1) 726,730 365,975 Total 3,123,002 2,833,293 Current portion (40,016 ) (40,099 ) Long-term portion 3,082,986 2,793,194 Unamortized deferred financing costs (2) (43,020 ) (46,669 ) Long-term portion less unamortized debt discount and deferred financing costs $ 3,039,966 $ 2,746,525 (1) At December 31, 2016, MIC Corporate included $376.8 million in long-term debt, net of the unamortized debt discount of $25.7 million, related to the $402.5 million convertible senior notes issued in October, 2016. See further discussions below. (2) The weighted average remaining life of the deferred financing costs at December 31, 2016 was 6.2 years.
Schedule of Future Maturities of Long-Term Debt	2017 $ 40,016 2018 51,086 2019 402,157 2020 95,084 2021 480,888 Thereafter 2,079,512 Total $ 3,148,743
Schedule of Interest Expense Recognized	Contractual interest expense $ 1,969 Amortization of debt discount 1,007 Amortization of deferred financing costs 306 Total interest expense $ 3,282
Convertible Debt	Liability Component: Principal $ 402,500 Unamortized debt discount (25,741 ) Unamortized deferred financing costs (9,934 ) Net carrying amount $ 366,825 Equity Component $ 26,748
Senior Notes [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Senior Notes, Series A Senior Notes, Series B Amount Outstanding at $325.0 million $275.0 million Maturity May 2025 May 2027 Amortization Payable at maturity Payable at maturity Interest Rate 3.92% per annum 4.02% per annum Security Unsecured Unsecured
Contracted Power and Energy Businesses [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Term Loan Facilities Term Loan Facility Borrower Solar Facilities – Term Loans Wind Facilities – Term Loan Facilities $201.7 million outstanding balance at December 31, 2016 $142.2 million outstanding balance at December 31, 2016 Maturity September 2023 to December 2036 December 2027 Amortization Fully amortizing through maturity Fully amortizing through maturity Interest Type Fixed and Floating Floating Interest Rate Fixed: 4.0% to 5.6%; Floating: LIBOR plus 2.00% LIBOR plus 1.625% at December 31, 2016; The margin increases by 0.25% every five years through maturity Collateral First lien on the following: First lien on the following: • Project revenues; • All property and assets of the Borrower and project companies; and • Equity of the Borrower; • Equity interests in the Borrower • All property and assets of the Borrower; and • Insurance policies and claims or proceeds. Facility Terms Term Loan Facilities Term Loan Facility Mandatory Prepayment • With net proceeds that equal or exceed $250,000 to $500,000 from the sale of assets not used for replacement of assets; • With net proceeds that equal or exceed $500,000 from the sale of assets; • With insurance proceeds that exceed from $250,000 to $1.0 million not used to repair, restore or replace assets; • With insurance proceeds that exceed $10.0 million not used to repair, restore or replace assets; • With condemnation proceeds that exceed from $250,000 to $1.0 million not used to repair, restore or replace assets; and • With Guaranteed Performance commitment liquidated damages in excess of $250,000; and • With net proceeds from equity and certain debt issuances. • With amount necessary to reduce debt to within the revised projected debt service coverage ratio following a substantial change such as additional wind turbines not in engineers plan.
Revolving Credit Facility [Member] | United States- IMTT [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms USD Revolving Credit Facility CAD Revolving Credit Facility Total Committed Amount $550.0 million $50.0 million Amount Outstanding at $32.0 million Undrawn Maturity May 2020 May 2020 Amortization Revolving, payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 1.50% at December 31, 2016 Bankers’ Acceptances Rate plus 1.50% at December 31, 2016 Commitment Fees 0.225% at December 31, 2016 0.225% at December 31, 2016 Security Unsecured Unsecured
Revolving Credit Facility [Member] | MIC Corporate [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Senior Secured Revolving July 2014 October 2016 Total Committed Amount $410.0 million — — Amount Outstanding at December 31, 2016 Undrawn $350.0 million $376.8 million, net of unamortized discount of $25.7 million Maturity July 2019 July 2019 October 2023 Amortization Revolving, payable at maturity Payable at maturity or convertible at the holder’s option into the Company’s shares Payable at maturity or convertible at the holder’s option into cash, the Company’s shares or a combination thereof only upon satisfaction of one or more conditions set forth in the indenture Interest Rate LIBOR plus 1.75% at December 31, 2016 2.875% payable on January 15 and July 15 of each year 2.0% payable on April 1 and October 1 of each year Commitment Fees 0.275% at December 31, 2016 — — Security Secured Unsecured Unsecured
Revolving Credit Facility [Member] | Hawaii Gas Business [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Holding Company Debt Operating Company Debt Borrowers HGC Holdings LLC (HGC) The Gas Company, LLC (TGC) Facilities $80.0 million Term Loan (fully drawn at December 31, 2016) $100.0 million Senior Secured Notes (fully drawn at December 31, 2016) $60.0 million Revolving Credit Facility (undrawn at December 31, 2016) Maturity February 2021, subject to two 1-year extensions at borrower’s option August 2022 February 2021, subject to two 1-year extensions at borrower’s option Amortization Payable at maturity Payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 1.75% or Base Rate: 0.75% above the greater of the prime rate or the federal funds rate plus 0.5% 4.22% payable semi-annually LIBOR plus 1.25% or Base Rate: 0.25% above the greater of the prime rate or the federal funds rate plus 0.5% Commitment Fees ___ ___ 0.225% on the undrawn portion Collateral First lien on all assets of HGC and its subsidiaries First lien on all assets of TGC and its subsidiaries First lien on all assets of TGC and its subsidiaries
Bayonne Energy Center [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Term Financing Revolving Credit Facility Total Committed Amount $275.0 million $25.0 million Amount Outstanding at December 31, 2016 $261.0 million Undrawn Maturity August 2022 August 2022 Amortization $10.0 million per annum paid in equal quarterly installments with the balance payable at maturity Revolving, payable at maturity Interest Rate LIBOR plus 2.125% from August 2015 to August 2020; and LIBOR plus 2.125% from August 2015 to August 2020; and LIBOR plus 2.375% from August 2020 through maturity LIBOR plus 2.375% from August 2020 through maturity Commitment Fee — 0.50% per annum Collateral First lien on all assets (subject to certain exceptions) First lien on all assets (subject to certain exceptions)
NJEDA Bonds [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms New Jersey Economic Development Authority Amount Outstanding at December 31, 2016 $36.3 million Maturity December 2027 Amortization Payable at maturity, subject to mandatory tender in May 2022 Interest Rate One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% Security Unsecured
LA Bonds [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Louisiana Public The Industrial Louisiana Public Louisiana Public Louisiana Public Amount Outstanding at December 31, 2016 $50.0 million $165.0 million $85.0 million $90.9 million $81.8 million Maturity June 2043 June 2043 August 2046 December 2040 December 2040 Amortization Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Payable at maturity, subject to mandatory tender in May 2022 Interest Rate One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 75% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% One-month LIBOR plus Revolving Credit Facility margin plus 0.625% multiplied by 67% Security Unsecured Unsecured Unsecured Unsecured Unsecured
A A FBO [Member]
Debt Instrument [Line Items]
Schedule of Material Terms	Facility Terms Term Loan Facility Revolving Credit Facility Facilities $400.0 million senior secured first lien term loan (fully drawn at December 31, 2016) $350.0 million senior secured first lien revolving credit facility ($48.0 million outstanding at December 31, 2016) Maturity October 7, 2021 October 7, 2021 Amortization • 2.5% of the initial principal balance per annum for the first year; . Revolving, payable at maturity • 5.0% of the initial principal balance per annum for the next two years; and • 7.5% of the initial principal balance per annum until maturity Interest Type Floating Floating Interest Rate • LIBOR plus 1.50% to 2.25% or Alternate Base Rate (ABR) plus 0.50% to 1.25%, in each case depending on total leverage ratio. ABR is the highest of (i) the prime rate, (ii) the federal funds rate plus 0.5% and (iii) one-month LIBOR plus 1.0% • LIBOR plus 1.50% to 2.25% or ABR plus 0.50% to 1.25%, in each case depending on total leverage ratio Commitment Fees — 0.25% to 0.35% on the undrawn portion, depending on total leverage ratio Facility Terms Term Loan Facility Revolving Credit Facility Covenants Maintenance of a maximum total leverage ratio; limitations on, among other things, distributions and other restricted payments, incurrence of debt, liens, fundamental changes, asset sales, investments, affiliate transactions and sale and leasebacks, in each case subject to certain exceptions. Maintenance of a maximum total leverage ratio; limitations on, among other things, distributions and other restricted payments, incurrence of debt, liens, fundamental changes, asset sales, investments, affiliate transactions and sale and leasebacks, in each case subject to certain exceptions. Collateral First priority security interest in (x) the equity securities of AA FBO and certain of its subsidiaries and (y) the personal and material real property of Holdings, AA FBO and certain of its subsidiaries (in each case subject to certain exceptions) First priority security interest in (x) the equity securities of AA FBO and certain of its subsidiaries and (y) the personal and material real property of Holdings, AA FBO and certain of its subsidiaries (in each case subject to certain exceptions) Mandatory Prepayment • With net proceeds from the sale of assets in excess of $10.0 million or from certain insurance recoveries in excess of $5.0 million, that are not reinvested • With net proceeds of debt issuances by Holdings, AA FBO and its restricted subsidiaries (other than certain permitted debt)

Derivative Instruments and He35

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Value of Derivative Instruments	The Company’s fair value measurements of its derivative instruments and the related location of the assets and liabilities within the consolidated balance sheets at December 31, 2016 and December 31, 2015 were ($ in thousands): Assets (Liabilities) (1) Balance Sheet Location 2016 2015 Fair value of derivative instruments – current assets $ 5,514 $ — Fair value of derivative instruments – noncurrent assets 30,781 1,810 Total derivative contracts – assets $ 36,295 $ 1,810 Fair value of derivative instruments – current liabilities $ (9,297 ) $ (19,628 ) Fair value of derivative instruments – noncurrent liabilities (5,966 ) (15,698 ) Total derivative contracts – liabilities $ (15,263 ) $ (35,326 ) (1) Fair value measurements at reporting date were made using significant other observable inputs (level 2).
Schedule of Location of Hedging Activities	The Company’s hedging activities for the years ended December 31, 2016, 2015 and 2014 and the related location within the consolidated financial statements were ($ in thousands): Amount of Gain (Loss) Recognized in Financial Statement Account 2016 2015 2014 Interest expense – interest rate caps $ 8,124 $ — $ (1 ) Interest expense – interest rate swaps (1) (13,107 ) (28,454 ) (19,483 ) Cost of product sales – commodity swaps 13,914 (6,458 ) (571 ) Other expense – commodity swaps — — (2,541 ) Total $ 8,931 $ (34,912 ) $ (22,596 ) (1) Interest expense for the year ended December 31, 2014 includes $18.6 million of derivative losses and $856,000 for amounts reclassified from accumulated other comprehensive loss for the interest rate swap contracts.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following represents the changes and balances to the components of accumulated other comprehensive loss for the years ended December 31, 2016, 2015 and 2014 ($ in thousands): Cash Flow (1) Post-Retirement (2) Translation (3) Total Noncontrolling Total Balance at December 31, 2013 $ (636 ) $ (8,021 ) $ (46 ) $ (8,703 ) $ 258 $ (8,445 ) Reclassification of realized losses of derivatives into earnings 636 — — 636 (258 ) 378 Change in post-retirement benefit — (10,816 ) — (10,816 ) — (10,816 ) Translation adjustment — — (4,813 ) (4,813 ) 2,146 (2,667 ) Balance at December 31, 2014 $ — $ (18,837 ) $ (4,859 ) $ (23,696 ) $ 2,146 $ (21,550 ) Change in post-retirement benefit — 4,049 — 4,049 — 4,049 Translation adjustment — — (9,671 ) (9,671 ) 3,877 (5,794 ) Balance at December 31, 2015 $ — $ (14,788 ) $ (14,530 ) $ (29,318 ) $ 6,023 $ (23,295 ) Change in post-retirement benefit — (2,017 ) — (2,017 ) — (2,017 ) Translation adjustment — — 2,375 2,375 (1,434 ) 941 Purchase of noncontrolling (4) — — — — (4,589 ) (4,589 ) Balance at December 31, 2016 $ — $ (16,805 ) $ (12,155 ) $ (28,960 ) $ — $ (28,960 ) (1) Reclassification of realized losses of derivatives is composed of (i) pre-tax derivative losses into interest expense of $856,000 and the related tax benefit of $340,000 in the consolidated statements of operations; and (ii) pre-tax derivative losses of $185,000 as an adjustment to investment in unconsolidated business, and an adjustment to deferred taxes of $65,000, in the consolidated balance sheet for the year ended December 31, 2014. For the year ended December 31, 2014, the Company wrote-off $162,000 for the amount related to the investment in unconsolidated business and related taxes of $57,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (2) Change in post-retirement benefit plans is presented net of tax benefit of $1.4 million, tax expense of $2.7 million and tax benefit of $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, change in post-retirement benefit plans also includes a write-off of the remaining balance of $6.5 million and the related taxes of $2.3 million, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (3) Translation adjustment is presented net of tax expense of $618,000 and tax benefits of $3.9 million and $2.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, translation adjustment also includes a write-off of the remaining balance of $66,000 and the related taxes of $23,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations. (4) On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss.
Schedule of Dividends	The Company’s Board of Directors have made or declared the following dividends during the years ended December 31, 2016, 2015 and 2014: Declared Period Covered $ per Record Date Payable Date February 17, 2017 Fourth quarter 2016 $ 1.31 March 3, 2017 March 8, 2017 October 27, 2016 Third quarter 2016 1.29 November 10, 2016 November 15, 2016 July 28, 2016 Second quarter 2016 1.25 August 11, 2016 August 16, 2016 April 28, 2016 First quarter 2016 1.20 May 12, 2016 May 17, 2016 February 18, 2016 Fourth quarter 2015 1.15 March 3, 2016 March 8, 2016 October 29, 2015 Third quarter 2015 1.13 November 13, 2015 November 18, 2015 July 30, 2015 Second quarter 2015 1.11 August 13, 2015 August 18, 2015 April 30, 2015 First quarter 2015 1.07 May 14, 2015 May 19, 2015 February 17, 2015 Fourth quarter 2014 1.02 March 2, 2015 March 5, 2015 October 27, 2014 Third quarter 2014 0.98 November 10, 2014 November 13, 2014 July 3, 2014 Second quarter 2014 0.95 August 11, 2014 August 14, 2014 April 28, 2014 First quarter 2014 0.9375 May 12, 2014 May 15, 2014 February 18, 2014 Fourth quarter 2013 0.9125 March 3, 2014 March 6, 2014
Schedule of Stock Issued to Board of Directors	Date of Grant Stock Units (1) Price of Stock Date of Vesting May 21, 2014 12,525 $ 59.89 May 19, 2015 June 18, 2015 (2) 8,660 86.61 May 17, 2016 May 18, 2016 (2) (3) 8,604 69.72 (4) November 1, 2016 (2) (5) 991 81.93 (4) (1) Stock units granted refer (i) from and after the time of the Conversion, to common stock and (ii) prior to the Conversion, LLC interests. (2) Restricted stock units granted under the 2014 Plan. (3) Restricted stock units are net of forfeitures of 2,151 restricted stock units due to the retirement of an independent director on September 30, 2016. (4) Date of vesting will be the day immediately preceding the 2017 annual meeting of the Company’s stockholders. (5) Represents additional restricted stock unit grants to a new independent director.

Reportable Segments (Tables)

Reportable Segments (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of EBITDA for Reportable Segments	Year Ended December 31, 2016 IMTT Atlantic Contracted MIC Total Reportable Net income $ 83,142 $ 59,538 $ 14,093 $ 35,744 $ 192,517 Interest expense, net 38,752 33,961 21,286 5,559 99,558 Provision for income taxes 57,736 39,889 14,328 20,441 132,394 Depreciation 123,346 41,493 51,120 10,533 226,492 Amortization of intangibles 11,039 49,166 4,428 792 65,425 Pension expense 7,219 110 — 1,272 8,601 Other non-cash expense (income) 657 905 (7,047 ) (11,539 ) (17,024 ) EBITDA excluding non-cash items $ 321,891 $ 225,062 $ 98,208 $ 62,802 $ 707,963 Year Ended December 31, 2015 IMTT Atlantic Contracted MIC Total Reportable Net income (loss) $ 74,726 $ 22,805 $ (7,152 ) $ 23,993 $ 114,372 Interest expense, net 37,378 35,735 28,390 7,279 108,782 Provision for income taxes 51,520 16,081 4,887 14,261 86,749 Depreciation 120,950 40,249 45,490 8,554 215,243 Amortization of intangibles 11,052 86,102 3,500 781 101,435 Pension expense 6,063 112 — 1,125 7,300 Other non-cash expense (income) 378 2,533 (6,959 ) 4,090 42 EBITDA excluding non-cash items $ 302,067 $ 203,617 $ 68,156 $ 60,083 $ 633,923 Year Ended December 31, 2014 IMTT (1) Atlantic Contracted MIC Total Reportable Net income (loss) $ 34,948 $ 36,964 $ (6,242 ) $ 21,329 $ 86,999 Interest expense, net 10,864 40,618 8,606 7,091 67,179 Provision for income taxes 25,768 25,096 823 12,635 64,322 Depreciation (2) 47,475 28,264 19,132 7,945 102,816 Amortization of intangibles 5,091 35,514 843 1,247 42,695 Pension expense 3,410 114 — 624 4,148 Other non-cash expense (income) 195 1,361 (439 ) 6,085 7,202 EBITDA excluding non-cash items $ 127,751 $ 167,931 $ 22,723 $ 56,956 $ 375,361 (1) Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition. (2) Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations. Reconciliation of total reportable segments’ EBITDA excluding non-cash items to consolidated net income (loss) before income taxes were ($ in thousands): Year Ended December 31, 2016 2015 2014 Total reportable segments EBITDA excluding non-cash items (1) $ 707,963 $ 633,923 $ 375,361 Interest income 132 55 112 Interest expense (116,933 ) (123,079 ) (73,196 ) Depreciation (2) (226,492 ) (215,243 ) (102,816 ) Amortization of intangibles (65,425 ) (101,435 ) (42,695 ) Selling, general and administrative expenses – Corporate and Other (13,056 ) (11,575 ) (15,526 ) Fees to Manager – related party (68,486 ) (354,959 ) (168,182 ) Gain from acquisition/divestiture of businesses — — 1,027,054 Equity in earnings and amortization charges of investee (1) — — 26,391 Pension expense (8,601 ) (7,300 ) (4,148 ) Other income (expense), net 17,024 645 (7,446 ) Total consolidated net income (loss) before income taxes $ 226,126 $ (178,968 ) $ 1,014,909 (1) Subsequent to July 16, 2014, the date of the IMTT Acquisition, total reportable segments' EBITDA excluding non-cash items includes the results of IMTT’s EBITDA excluding non-cash items. Prior to July 16, 2014, MIC accounted for its 50% investment in IMTT under the equity method of accounting. As such, MIC’s 50% share of IMTT’s net income was reported in equity in earnings and amortization charges of investee in the above table for the period prior to July 16, 2014. (2) Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations.
Schedule of Revenue From External Customers	Year Ended December 31, 2016 IMTT Atlantic Contracted MIC Intersegment Total Service revenue $ 532,472 $ 740,209 $ — $ 20,762 $ (4,881 ) $ 1,288,562 Product revenue — — 150,010 213,159 — 363,169 Total revenues $ 532,472 $ 740,209 $ 150,010 $ 233,921 $ (4,881 ) $ 1,651,731 Year Ended December 31, 2015 IMTT Atlantic Contracted MIC Total Service revenue $ 550,041 $ 738,460 $ — $ — $ 1,288,501 Product revenue — — 123,797 226,952 350,749 Total revenues $ 550,041 $ 738,460 $ 123,797 $ 226,952 $ 1,639,250 Year Ended December 31, 2014 IMTT (1) Atlantic Contracted MIC Total Service revenue $ 255,934 $ 779,261 $ 29,487 $ — $ 1,064,682 Product revenue — — 19,779 264,621 284,400 Financing and equipment lease income — — 1,836 — 1,836 Total revenues $ 255,934 $ 779,261 $ 51,102 $ 264,621 $ 1,350,918 (1) Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition.
Schedule of Capital Expenditures	Year Ended December 31, 2016 2015 2014 IMTT $ 96,865 $ 96,990 $ 47,376 Atlantic Aviation 113,092 64,385 43,691 Contracted Power 69,268 15,636 14,376 MIC Hawaii 35,459 17,137 18,503 Total $ 314,684 $ 194,148 $ 123,946
Schedule of Assets of Reportable Segments	Property, Equipment, Goodwill Total Assets 2016 2015 2016 2015 2016 2015 (1) IMTT $ 2,218,256 $ 2,238,654 $ 1,411,029 $ 1,410,668 $ 3,978,379 $ 4,000,079 Atlantic Aviation 465,096 390,188 468,419 464,722 1,564,668 1,502,512 Contracted Power 1,383,289 1,274,557 21,628 21,628 1,516,602 1,411,233 MIC Hawaii 279,863 212,764 123,333 120,193 501,713 386,080 Total assets of reportable segments $ 4,346,504 $ 4,116,163 $ 2,024,409 $ 2,017,211 $ 7,561,362 $ 7,299,904 Corporate and other 32 — — — (2,109 ) 8,900 Total consolidated assets $ 4,346,536 $ 4,116,163 $ 2,024,409 $ 2,017,211 $ 7,559,253 $ 7,308,804 (1) Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
United States- IMTT [Member]
Schedule of Segment Information	As of, and for the (1) Revenue $ 311,533 Net income $ 57,725 Interest expense, net 16,375 Provision for income taxes 38,265 Depreciation and amortization 40,922 Pension expense 4,025 Other non-cash expenses 112 EBITDA excluding non-cash items (2) $ 157,424 Capital expenditures paid $ 59,868 Property, equipment, land and leasehold improvements, net 1,289,245 Total assets 1,415,378 (1) Amounts represent financial position of IMTT business prior to July 16, 2014, the date of the IMTT Acquisition. (2) The Company defines EBITDA excluding non-cash items as net income (loss) or earnings — the most comparable GAAP measure
Schedule of Selected Consolidated Financial Data	Year Ended Revenue $ 1,662,451 Net income attributable to MIC (1) 77,923 (1) The tax rate used to calculate net income attributable to MIC was 35.0%.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of Dividends Paid to Manager	Since January 1, 2014, the Company paid the Manager cash dividends on shares held for the following periods: Declared Period Covered $ per Record Date Payable Date Cash Paid February 17, 2017 Fourth quarter 2016 $ 1.31 March 3, 2017 March 8, 2017 (1) October 27, 2016 Third quarter 2016 1.29 November 10, 2016 November 15, 2016 $ 5,620 July 28, 2016 Second quarter 2016 1.25 August 11, 2016 August 16, 2016 8,743 April 28, 2016 First quarter 2016 1.20 May 12, 2016 May 17, 2016 6,981 February 18, 2016 Fourth quarter 2015 1.15 March 3, 2016 March 8, 2016 6,510 October 29, 2015 Third quarter 2015 1.13 November 13, 2015 November 18, 2015 6,052 July 30, 2015 Second quarter 2015 1.11 August 13, 2015 August 18, 2015 5,693 April 30, 2015 First quarter 2015 1.07 May 14, 2015 May 19, 2015 7,281 February 17, 2015 Fourth quarter 2014 1.02 March 2, 2015 March 5, 2015 4,905 October 27, 2014 Third quarter 2014 0.98 November 10, 2014 November 13, 2014 4,438 July 3, 2014 Second quarter 2014 0.95 August 11, 2014 August 14, 2014 3,402 April 28, 2014 First quarter 2014 0.9375 May 12, 2014 May 15, 2014 3,180 February 18, 2014 Fourth quarter 2013 0.9125 March 3, 2014 March 6, 2014 2,945 (1) The amount of dividend payable to the Manager for the fourth quarter of 2016 will be determined on March 3, 2017, the record date.
Schedule of Base Management Fees and Performance Fees	Period Base Management Performance Shares 2016 Activities: Fourth quarter 2016 $ 18,916 $ — 230,773 (1) Third quarter 2016 18,382 — 232,488 Second quarter 2016 16,392 — 232,835 First quarter 2016 14,796 — 234,179 2015 Activities: Fourth quarter 2015 $ 17,009 $ — 227,733 Third quarter 2015 18,118 — 226,914 Second quarter 2015 18,918 135,641 1,167,873 (2) First quarter 2015 16,545 148,728 2,068,038 2014 Activities: Fourth quarter 2014 $ 14,192 $ — 208,122 Third quarter 2014 13,915 116,586 947,583 (3) Second quarter 2014 9,535 4,960 243,329 First quarter 2014 8,994 — 164,546 (1) The Manager elected to reinvest all of the monthly base management fees for the fourth quarter of 2016 in shares. The Company issued 230,773 shares for the quarter ended December 31, 2016, including 76,914 shares that were issued in January 2017 for the December 2016 monthly base management fee. (2) In July 2015, the Board requested, and the Manager agreed, that $67.8 million of the performance fee for the quarter ended June 30, 2015 be settled in cash in July 2015 to minimize dilution. The remaining $67.8 million obligation was settled and reinvested in 944,046 shares by the Manager on August 1, 2016 using the June 2016 volume weighted average share price of $71.84. (3) In October 2014, the Board requested, and the Manager agreed, that $65.0 million of the performance fee for the quarter ended September 30, 2014 be settled in cash using the proceeds from the sale of the district energy business to minimize dilution. The remainder of the fee of $51.6 million was reinvested in additional shares of MIC.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Taxes	Year Ended December 31, 2016 2015 2014 Current taxes: Federal $ — $ (6,884 ) $ 463 State 7,310 457 2,134 Total current tax provision (benefit) $ 7,310 $ (6,427 ) $ 2,597 Deferred taxes: Federal $ 79,796 $ (46,744 ) $ (23,339 ) State (1,185 ) (14,348 ) (1,435 ) Total deferred tax provision (benefit) 78,611 (61,092 ) (24,774 ) Change in valuation allowance (14,664 ) 2,358 (2,197 ) Total tax provision (benefit) $ 71,257 $ (65,161 ) $ (24,374 )
Schedule of Deferred Tax Assets and Liabilities	At December 31, 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 186,948 $ 189,060 Deferred revenue 8,681 9,383 Accrued compensation 13,894 13,837 Accrued expenses 32,114 30,133 Unrealized losses on derivative instruments, net — 6,482 Other 5,942 5,496 Total gross deferred tax assets 247,579 254,391 Less: valuation allowance (4,319 ) (18,983 ) Net deferred tax assets $ 243,260 $ 235,408 Deferred tax liabilities: Intangible assets $ (145,199 ) $ (140,128 ) Investment basis difference (75,105 ) (32,816 ) Property and equipment (892,382 ) (877,065 ) Unrealized gains on derivative instruments, net (14,104 ) — Equity component convertible senior notes (11,882 ) — Prepaid expenses (704 ) (2,235 ) Total deferred tax liabilities (1,139,376 ) (1,052,244 ) Net deferred tax liabilities $ (896,116 ) $ (816,836 )
Schedule of Reconciliation of Income Taxes	Year Ended December 31, 2016 2015 2014 Tax provision (benefit) at U.S. statutory rate $ 79,144 $ (62,639 ) $ 355,218 Permanent differences and other (1,924 ) 1,299 3,418 State income taxes, net of federal benefit 8,958 (10,082 ) (2,111 ) Income attributable to noncontrolling interest (257 ) 3,903 2,328 Gain from acquisition/divestiture of businesses — — (347,772 ) Tax effect of federal dividends received deduction — — (8,029 ) Basis adjustment for equity method investment — — (25,229 ) Change in valuation allowance (14,664 ) 2,358 (2,197 ) Total tax provision (benefit) $ 71,257 $ (65,161 ) $ (24,374 )

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Schedule of Future Minimum Rental Commitments	Future minimum rental commitments at December 31, 2016 are ($ in thousands): 2017 $ 47,460 2018 45,714 2019 42,923 2020 41,328 2021 40,290 Thereafter 478,087 Total $ 695,802

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Pension and Other Postretirement Benefit Contributions [Abstract]
Funded Status	The funded status at December 31, 2016 and 2015, are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Funded status Funded status at end of year $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) Net amount recognized in balance sheet (1) $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) Amounts recognized in balance sheet consisting of: Noncurrent assets $ — $ — $ — $ — $ — $ 222 $ — $ 222 Current liabilities — — — — (1,160 ) (916 ) (1,160 ) (916 ) Noncurrent liabilities (4,216 ) (7,219 ) (44,915 ) (39,181 ) (17,277 ) (13,057 ) (66,408 ) (59,457 ) Net amount recognized in balance sheet (1) $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 ) (1) Generally accepted accounting principles require measurement of defined benefit pension liabilities utilizing current discount rates. Statutory funding formulas permit measurement of defined benefit pension liabilities utilizing discount rates based on a 25-year average of those rates, which more closely matches the expected payout period for those liabilities. The IMTT and Hawaii Gas defined benefit pension plans both exceed 100% of the statutory funding target as of December 31, 2016. Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss for the years ended December 31, 2016 and 2015 are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Prior service credit $ — $ — $ — $ — $ 95 $ 110 $ 95 $ 110 Accumulated loss (12,000 ) (12,698 ) (9,577 ) (9,926 ) (5,594 ) (1,140 ) (27,171 ) (23,764 ) Accumulated other comprehensive loss (12,000 ) (12,698 ) (9,577 ) (9,926 ) (5,499 ) (1,030 ) (27,076 ) (23,654 ) Net periodic benefit cost in excess (deficit) of cumulative employer contributions 7,784 5,479 (35,338 ) (29,255 ) (12,938 ) (12,721 ) (40,492 ) (36,497 ) Net amount recognized in balance sheet $ (4,216 ) $ (7,219 ) $ (44,915 ) $ (39,181 ) $ (18,437 ) $ (13,751 ) $ (67,568 ) $ (60,151 )
Components of Net Periodic Benefit Cost and Other Changes in Other Comprehensive Income for Plans	The components of net periodic benefit cost and other changes in other comprehensive (income) loss for the plans are shown below ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2014 2016 2015 2014 2016 2015 2014 2016 2015 2014 Components of net periodic benefit cost: Service cost $ 744 $ 841 $ 716 $ 6,285 $ 6,853 $ 2,799 $ 810 $ 911 $ 409 $ 7,839 $ 8,605 $ 3,924 Interest cost 2,046 1,988 1,988 6,172 5,914 2,530 974 912 480 9,192 8,814 4,998 Expected return on plan assets (2,448 ) (2,670 ) (2,268 ) (6,374 ) (7,020 ) (3,049 ) (502 ) (585 ) (183 ) (9,324 ) (10,275 ) (5,500 ) Recognized actuarial loss (gain) 854 883 122 — (534 ) 579 91 (31 ) 200 945 318 901 Amortization of prior service (cost) credit — — — — (78 ) 78 (15 ) (5 ) 5 (15 ) (83 ) 83 Net periodic benefit cost $ 1,196 $ 1,042 $ 558 $ 6,083 $ 5,135 $ 2,937 $ 1,358 $ 1,202 $ 911 $ 8,637 $ 7,379 $ 4,406 Other changes recognized in other comprehensive (income) loss: Prior service credit arising during the year $ — $ — $ — $ — $ — $ — $ — $ (110 ) $ — $ — $ (110 ) $ — Net loss (gain) arising during the year 156 268 7,925 8,428 (5,873 ) 15,844 4,545 (836 ) 1,406 13,129 (6,441 ) 25,175 Liability gain due to curtailment — — — (8,777 ) — — — — — (8,777 ) — — Amortization of prior service cost (credit) — — — — 78 (78 ) 15 5 (5 ) 15 83 (83 ) Amortization of (loss) (854 ) (883 ) (122 ) — 534 (579 ) (91 ) 31 (200 ) (945 ) (318 ) (901 ) Total recognized in other comprehensive (income) loss $ (698 ) $ (615 ) $ 7,803 $ (349 ) $ (5,261 ) $ 15,187 $ 4,469 $ (910 ) $ 1,201 $ 3,422 $ (6,786 ) $ 24,191 The estimated amounts that will be amortized from accumulated other comprehensive (income) loss over the next year are presented in the following table ($ in thousands): HG DB IMTT DB Other Total 2016 2015 2016 2015 2016 2015 2016 2015 Amortization of prior service cost (credit) $ — $ — $ — $ — $ (15 ) $ (15 ) $ (15 ) $ (15 ) Amortization of net loss 794 854 — — 264 76 1,058 930 The assumptions used in accounting for the HG DB Plan Benefits, IMTT DB Plan Benefits and Other Plan Benefits are: HG DB Plan Benefits IMTT DB Plan Benefits Other Plan Benefits 2016 2015 2014 2016 2015 2014 2016 2015 2014 Weighted average assumptions to determine benefit obligations: Discount rate 4.00% 4.20% 3.90% 4.30% 4.65% 4.25% 3.56% to 4.25% 3.78% to 4.55% 3.45% to 4.15% Rate of compensation increase N/A N/A N/A 4.57% 4.57% 4.57% 4.57% (1) 4.57% (1) 4.57% (1) Measurement date December 31 December 31 December 31 December 31 December 31 December 31 December 31 December 31 December 31 Weighted average assumptions to determine net cost: Discount rate 4.20% 3.90% 4.70% 4.65% 4.25% 4.55% 3.78% to 4.55% 3.45% to 4.15% 4.20% to 4.45% Expected long-term rate of return on plan assets during fiscal year 5.90% 5.90% 5.90% 6.75% 7.00% 7.00% 6.25% (2) 7.00% (2) 7.00% (2) Rate of compensation increase N/A N/A N/A 4.57% 4.57% 4.57% 4.57% (1) 4.57% (1) 4.57% (1) Assumed healthcare cost trend rates: Initial health care cost trend rate 7.20% to 7.25% 7.50% 7.75% to 7.80% Ultimate rate 4.50% to 5.00% 4.50% to 5.00% 4.50% to 5.00% Year ultimate rate is reached 2025 to 2028 2025 to 2028 2025 to 2028 (1) Only applies to IMTT post-retirement life insurance plan. (2) Only applies to IMTT Union Plan.
DB Plan Weighted Average Asset Allocation	The weighted average asset allocation at December 31, 2016 and 2015 was: HG DB IMTT DB Other 2016 2015 2016 2015 2016 2015 Equity securities 56 % 60 % 51 % 58 % 51 % 58 % Fixed income securities 27 % 30 % 44 % 37 % 48 % 41 % Mixed income securities 7 % 8 % — — — — Private equity — — 4 % 3 % — — Cash 10 % 2 % 1 % 2 % 1 % 1 % Total 100 % 100 % 100 % 100 % 100 % 100 %
Asset Allocations of Hawaii Gas's Pension Benefits	The asset allocations as of December 31, 2016 and 2015 measurement dates were ($ in thousands): Fair Value Measurements at December 31, 2016 Total Quoted Prices Significant Significant Asset category: Cash and money market $ 5,890 $ 5,890 $ — $ — Equity securities: Domestic equities 63,552 63,552 — — International equities 15,727 15,727 — — Fixed income securities: Domestic fixed income 59,028 59,028 — — Domestic mixed income securities 3,401 3,401 — — Domestic private equity 3,428 — — 3,428 Total $ 151,026 $ 147,598 $ — $ 3,428 Fair Value Measurements at December 31, 2015 Total Quoted Prices Significant Significant Asset category: Cash and money market $ 3,138 $ 3,138 $ — $ — Equity securities: Domestic equities 66,290 66,290 — — International equities 20,473 20,473 — — Fixed income securities: Domestic fixed income 50,860 50,860 — — International fixed income 1,035 1,035 — — Domestic mixed income securities 3,401 3,401 — — Domestic private equity 2,680 — — 2,680 Total $ 147,877 $ 145,197 $ — $ 2,680
Estimated Future Benefit Payments	The estimated future benefit payments for the next ten years are ($ in thousands): HG DB Plan IMTT DB Plan Benefits Other Total 2017 $ 2,742 $ 7,363 $ 1,447 $ 11,552 2018 2,869 5,716 1,523 10,108 2019 2,933 6,529 1,618 11,080 2020 3,003 7,813 1,803 12,619 2021 3,064 7,103 1,779 11,946 Thereafter 15,520 41,805 8,882 66,207 Total $ 30,131 $ 76,329 $ 17,052 $ 123,512

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Data	The data shown below relates to the Company’s operations and includes all adjustments which the Company considers necessary for a fair presentation of such amounts. Quarter ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2016 Revenue $ 396,387 $ 397,579 $ 420,524 $ 437,241 Operating income 88,776 76,507 75,658 80,200 Net income attributable to MIC 22,355 19,192 42,026 72,808 Per share information attributable to MIC: Net income per share – basic $ 0.28 $ 0.24 $ 0.52 $ 0.89 Net income per share – diluted (1) 0.28 0.24 0.51 0.79 Cash dividends declared per share $ 1.20 $ 1.25 $ 1.29 $ 1.31 2015 Revenue $ 398,498 $ 423,689 $ 415,709 $ 401,354 Operating (loss) income (115,365 ) (75,301 ) 73,449 59,985 Net (loss) income attributable to MIC (89,002 ) (63,096 ) 10,638 32,923 Per share information attributable to MIC: Net (loss) income per share – basic $ (1.22 ) $ (0.80 ) $ 0.13 $ 0.41 Net (loss) income per share – diluted (1) (1.22 ) (0.80 ) 0.13 0.41 Cash dividends declared per share $ 1.07 $ 1.11 $ 1.13 $ 1.15 (1) Diluted net income (loss) per share reflects the effect of potentially dilutive shares assuming: (i) the restricted stock unit grants provided to the independent directors had been fully converted to shares on the grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued in July 2014 and October 2016 had been fully converted into shares on the issue date. The potentially dilutive shares are excluded in the calculation if the effect is anti-dilutive or when the Company has a net loss for the period.

Organization and Description 43

Organization and Description of Business (Narrative) (Details)	Dec. 31, 2016Item
Canada- IMTT [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of marine terminals	2
United States- IMTT [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of marine terminals	10
Atlantic Aviation [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of Airport Locations	69

Summary of Significant Accoun44

Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)		Mar. 31, 2015	Jul. 16, 2014	Jul. 15, 2014
Significant Accounting Policies [Line Items]
Equity interest acquired					50.00%
Number Of Solar Projects	7
Number of wind power generation facilities	2
Restricted cash	$ 16,500	$ 19,000
Restricted cash, current	16,420	18,946	[1]
Inventory Net, held for sale	14,300	14,300
Inventory Net, materials and supplies	$ 17,200	15,200
Restatement Adjustment [Member]
Significant Accounting Policies [Line Items]
Deferred income taxes		23,400
Minimum [Member]
Significant Accounting Policies [Line Items]
Debt issuance costs amortized period	5 years
Life of Purchase Power Agreements	20 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Debt issuance costs amortized period	23 years
Life of Purchase Power Agreements	25 years
IMTT [Member]
Significant Accounting Policies [Line Items]
Condition for consolidation, minimum ownership percentage	50.00%
Percentage of ownership interest accounted under equity method of accounting					50.00%	50.00%
Equity interest acquired						50.00%
Cost Method Investment in unconsolidated business	$ 8,800	$ 8,300
IMTT [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Term of contracts for the use of storage capacity at the various terminals	1 year
IMTT [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Term of contracts for the use of storage capacity at the various terminals	5 years
Bayonne Energy Center [Member]
Significant Accounting Policies [Line Items]
Equity interest acquired				100.00%
Percentage Of Contracted Tolling Agreement				62.50%
Bayonne Energy Center [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Weighted Average Life Of Tolling Agreements	11 years
Bayonne Energy Center [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Weighted Average Life Of Tolling Agreements	13 years
IMTT Acquisition [Member]
Significant Accounting Policies [Line Items]
Equity interest acquired					20.00%
MIC Hawaii [Member]
Significant Accounting Policies [Line Items]
Contract Backlog Revenue Expected to be Recognized	$ 75,000
MIC Hawaii [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Contract Backlog Revenue Expected to be Recognized term	2 years
MIC Hawaii [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Contract Backlog Revenue Expected to be Recognized term	3 years
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Summary of Significant Accoun45

Summary of Significant Accounting Policies (Schedule of Estimated Economic Useful Lives of Property Plant and Equipment) (Details)	12 Months Ended
	Dec. 31, 2016
Minimum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	10 years
Minimum [Member] | Leasehold and land improvements [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	5 years
Minimum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	3 years
Maximum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	68 years
Maximum [Member] | Leasehold and land improvements [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	40 years
Maximum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	62 years
Maximum [Member] | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Useful life	15 years

Summary of Significant Accoun46

Summary of Significant Accounting Policies (Schedule of Estimated Useful Lives of Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2016
Leasehold rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	25 years
Trade names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Minimum [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Minimum [Member] | Contract arrangements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Minimum [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum [Member] | Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	30 years
Maximum [Member] | Contract arrangements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	57 years
Maximum [Member] | Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years

Income (Loss) per Share (Narrat

Income (Loss) per Share (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2016

Sep. 30, 2016

[1]

Jun. 30, 2016

[1]

Mar. 31, 2016

[1]

Dec. 31, 2015

[1]

Sep. 30, 2015

[1]

Jun. 30, 2015

[1]

Mar. 31, 2015

[1]

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Oct. 31, 2016

Class of Stock [Line Items]

Antidilutive securities

4,177,097

4,619,253

0

Interest rate

2.00%

Earnings Per Share, Diluted, Total

$ 0.79

[1]

$ 0.51

$ 0.24

$ 0.28

$ 0.41

$ 0.13

$ (0.80)

$ (1.22)

$ 1.85

$ (1.39)

$ 16.1

Restricted stock unit grants forfeited during the period

2,151

MIC Corporate [Member]

Class of Stock [Line Items]

Interest rate

2.875%

Restricted stock unit grants May 20, 2013 [Member]

Class of Stock [Line Items]

Potentially dilutive shares

12,910

Restricted stock unit grants May 21, 2014 [Member]

Class of Stock [Line Items]

Antidilutive securities

12,525

Potentially dilutive shares

12,525

Restricted stock unit grants June 18, 2015 [Member]

Class of Stock [Line Items]

Antidilutive securities

8,660

Potentially dilutive shares

8,660

Restricted Stock Unit Grants May 18, 2016 [Member]

Class of Stock [Line Items]

Potentially dilutive shares

8,604

Dilutive [Member]

Class of Stock [Line Items]

Performance fee reinvested by the Manager

$ 67.8

$ 67.8

Antidilutive [Member]

Class of Stock [Line Items]

Performance fee reinvested by the Manager

$ 67.8

Restricted Stock Unit Grants November 1, 2016 [Member]

Class of Stock [Line Items]

Potentially dilutive shares

991

Restated [Member]

Class of Stock [Line Items]

Earnings Per Share, Diluted, Total

$ 16.01

[1]

Diluted net income (loss) per share reflects the effect of potentially dilutive shares assuming: (i) the restricted stock unit grants provided to the independent directors had been fully converted to shares on the grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued in July 2014 and October 2016 had been fully converted into shares on the issue date. The potentially dilutive shares are excluded in the calculation if the effect is anti-dilutive or when the Company has a net loss for the period.

Income (Loss) per Share (Schedu

Income (Loss) per Share (Schedule of Reconciliation of Number of Shares Used in Computing [Income (Loss)] per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net income (loss) attributable to MIC		$ 72,808		$ 42,026		$ 19,192		$ 22,355		$ 32,923		$ 10,638		$ (63,096)		$ (89,002)		$ 156,381	$ (108,537)	$ 1,042,028
Diluted net income (loss) attributable to MIC																		$ 151,858	$ (108,537)	$ 1,045,044
Denominator:
Weighted average number of shares outstanding: basic																		80,892,654	77,997,826	62,990,312
Dilutive effect of restricted stock unit grants																		9,589	0	12,637
Dilutive effect of fees to Manager-related party																		549,404	0	0
Weighted average number of shares outstanding: diluted																		82,218,627	77,997,826	64,925,565
Income (loss) per share:
Basic income (loss) per share attributable to MIC		$ 0.89		$ 0.52		$ 0.24		$ 0.28		$ 0.41		$ 0.13		$ (0.80)		$ (1.22)		$ 1.93	$ (1.39)	$ 16.54
Diluted income (loss) per share attributable to MIC		$ 0.79	[1]	$ 0.51	[1]	$ 0.24	[1]	$ 0.28	[1]	$ 0.41	[1]	$ 0.13	[1]	$ (0.80)	[1]	$ (1.22)	[1]	$ 1.85	$ (1.39)	$ 16.1
Convertible Senior Notes July 2014 [Member]
Numerator:
Interest expense attributable to convertible senior notes, net of taxes	[2]																	$ 0	$ 0	$ 3,016
Denominator:
Dilutive effect of convertible senior notes																		0	0	1,922,616
Convertible Senior Notes October 2016 [Member]
Numerator:
Interest expense attributable to convertible senior notes - October 2016, net of taxes																		$ (4,523)	$ 0	$ 0
Denominator:
Dilutive effect of convertible senior notes																		766,980	0	0
[1]	Diluted net income (loss) per share reflects the effect of potentially dilutive shares assuming: (i) the restricted stock unit grants provided to the independent directors had been fully converted to shares on the grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued in July 2014 and October 2016 had been fully converted into shares on the issue date. The potentially dilutive shares are excluded in the calculation if the effect is anti-dilutive or when the Company has a net loss for the period.
[2]	For the year ended December 31, 2014, diluted income per share attributable to MIC does not include the after-tax impact of the write-off of deferred financing costs attributable to the July 2014 2.875% Convertible Senior Notes. If the after-tax impact of deferred financing costs were added back to net income for the year ended December 31, 2014, the diluted income per share attributable to MIC would have been $16.01.

Income (Loss) per Share (Sche49

Income (Loss) per Share (Schedule of Shares Excluded from Calculation) (Details) - shares		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities		4,177,097	4,619,253	0
Restricted Stock Unit Grants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities		0	9,410	0
Fees to Manager- Related Party [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	[1]	0	449,126	0
Convertible Senior Notes July 2014 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities		4,177,097	4,160,717	0
[1]	Represents $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016. The weighted average potentially dilutive shares of common stock in the above table include shares assumed to have been reinvested in shares by the Manager in July 2015.

Property, Equipment, Land and50

Property, Equipment, Land and Leasehold Improvements (Schedule of Property and Equipment) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)MW	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Land		$ 304,240	$ 291,521
Easements		131	131
Buildings		41,711	41,049
Leasehold and land improvements		673,122	590,646
Machinery and equipment		3,764,553	3,455,776
Furniture and fixtures		35,454	29,547
Construction in progress		233,184	203,146
Property, Plant and Equipment, Gross, Total		5,052,395	4,611,816
Less: accumulated depreciation		(705,859)	(495,653)
Property, equipment, land and leasehold improvements, net		4,346,536	4,116,163	[1]
Goodwill		$ 2,024,409	$ 2,017,211	[1]
Multiple Fixed Based Operations [Member] | Land and Leasehold Improvements [Member] | Atlantic Aviation [Member]
Property, Plant and Equipment [Line Items]
Fixed assets impairment charge	$ 2,800
One Specific Fixed Based Operations [Member] | Land and Leasehold Improvements [Member] | Atlantic Aviation [Member]
Property, Plant and Equipment [Line Items]
Fixed assets impairment charge	$ 4,200
Acquisition [Member]
Property, Plant and Equipment [Line Items]
Capacity Of Plant | MW		80
Business acquisition, purchase price		$ 69,200
Property, equipment and leasehold improvements		132,300
Intangible assets - contractual arrangements		19,100
Accounts receivable		21,900
Goodwill		6,800
Liabilities assumed		78,200
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable And Accrued Expenses		6,900
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		$ 24,100
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Intangible Assets (Schedule of

Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Intangible Assets [Line Items]
Contractual arrangements		$ 912,728	$ 901,807
Non-compete agreements		10,014	9,665
Customer relationships		348,678	340,425
Leasehold rights		350	350
Trade names		16,091	16,091
Technology		8,760	8,760
Intangible assets, gross		1,296,621	1,277,098
Less: accumulated amortization		(407,650)	(342,206)
Intangible assets, net		888,971	934,892	[1]
Amortization of Intangible Assets		65,425	101,435		$ 42,695
Trade Names [Member]
Intangible Assets [Line Items]
Trade names		14,100
Atlantic Aviation [Member]
Intangible Assets [Line Items]
Amortization of Intangible Assets		49,166	$ 86,102		$ 35,514
Atlantic Aviation [Member] | Indefinite-lived Intangible Assets [Member]
Intangible Assets [Line Items]
Trade names		7,500
Atlantic Aviation [Member] | Multiple FBOs [Member] | Contractual Rights [Member]
Intangible Assets [Line Items]
Intangible impairment charge	$ 13,500
Atlantic Aviation [Member] | One specific FBO [Member] | Contractual Rights [Member]
Intangible Assets [Line Items]
Intangible impairment charge	$ 17,800
Hawaii Gas Company [Member]
Intangible Assets [Line Items]
Trade names		$ 6,600
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Intangible Assets (Schedule o52

Intangible Assets (Schedule of Estimated Future Amortization Expense) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2,017	$ 60,828
2,018	56,537
2,019	53,588
2,020	49,439
2,021	46,995
Thereafter	614,093
Total	$ 881,480

Intangible Assets (Schedule o53

Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Intangible Assets [Abstract]
Goodwill acquired in business combinations, net of disposals			$ 2,143,057
Accumulated impairment charges			(123,200)
Balance at December 31, 2015	[1]	$ 2,017,211
Goodwill related to 2016 acquisitions		6,837
Other		361	(2,646)
Balance at December 31, 2016		$ 2,024,409	$ 2,017,211	[1]
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Accrued Expenses [Abstract]
Payroll and related liabilities		$ 29,851	$ 26,740
Purchase of property and equipment		11,669	8,045
Interest		13,153	10,684
Insurance		3,957	6,361
Property tax		6,046	4,670
Other taxes	[1]	4,689	5,750
Other		14,369	16,277
Accrued expenses		$ 83,734	$ 78,527	[2]
[1]	Other taxes primarily consists of sales and franchise taxes.
[2]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)

Oct. 13, 2016USD ($)$ / shares

Oct. 07, 2016USD ($)

Jul. 15, 2016USD ($)

Feb. 10, 2016USD ($)

Aug. 10, 2015USD ($)

Jul. 15, 2014USD ($)$ / shares

Feb. 21, 2017USD ($)

Dec. 31, 2016USD ($)MW

Oct. 31, 2016USD ($)

Jul. 31, 2016USD ($)

May 31, 2015USD ($)

May 21, 2015USD ($)

Apr. 30, 2015

Mar. 31, 2015USD ($)MW

Jul. 31, 2014USD ($)

Mar. 31, 2015USD ($)MW

Jun. 02, 2015

Dec. 31, 2015USD ($)

Dec. 31, 2016USD ($)MW

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Oct. 28, 2016USD ($)

Oct. 06, 2016USD ($)

Aug. 31, 2016USD ($)

Feb. 29, 2016USD ($)

Jan. 22, 2014USD ($)

Debt Disclosure [Line Items]

Proceeds from Convertible senior notes

$ 402,500,000

$ 0

$ 350,000,000

Current and long-term debt

$ 3,123,002,000

$ 2,833,293,000

$ 3,123,002,000

2,833,293,000

Interest Rate

2.00%

Unamortized deferred financing costs

[1]

$ 43,020,000

46,669,000

$ 43,020,000

46,669,000

MIC Corporate [Member]

Debt Disclosure [Line Items]

Current and long-term debt

[2]

726,730,000

365,975,000

726,730,000

365,975,000

Interest Rate

2.875%

Atlantic Aviation [Member]

Debt Disclosure [Line Items]

Current and long-term debt

449,691,000

604,609,000

449,691,000

604,609,000

IMTT [Member]

Debt Disclosure [Line Items]

Current and long-term debt

1,140,975,000

1,127,223,000

1,140,975,000

1,127,223,000

Contracted Power [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 604,862,000

555,486,000

$ 604,862,000

555,486,000

Acquisition [Member]

Debt Disclosure [Line Items]

Electricity generating capacity | MW

80

80

Wind Power Generation Facilities [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Number of facilities

2

2

Bayonne Energy Center [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

4.00%

Amortizing term loan debt assumed

$ 509,100,000

$ 509,100,000

Variable Term Loan Interest Rate Floor

1.00%

Electricity generating capacity | MW

512

512

Solar Power Facilities [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Number of facilities

6

6

Solar Power Facilities [Member] | Contracted Power [Member] | Fixed Rate Term Loans [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 193,200,000

$ 193,200,000

Solar and wind power facilities [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Electricity generating capacity | MW

340

340

Solar and wind power facilities [Member] | Contracted Power [Member] | Floating Rate Term Loan [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 150,700,000

$ 150,700,000

Revolving Credit Facility [Member]

Debt Disclosure [Line Items]

Undrawn portion of line of credit

1,400,000,000

1,400,000,000

Revolving Credit Facility [Member] | Subsequent Event [Member]

Debt Disclosure [Line Items]

Undrawn portion of line of credit

$ 1,400,000,000

Revolving Credit Facility [Member] | MIC Corporate [Member]

Debt Disclosure [Line Items]

Borrowing capacity

410,000,000

$ 250,000,000

410,000,000

$ 410,000,000

410,000,000

Debt instrument, term

5 years

Fixed portion of interest rate component

1.75%

Repayment of revolving credit facility

$ 498,000,000

Drawn on revolver credit facility

$ 482,000,000

Maturity

Jul. 31, 2019

Revolving Credit Facility [Member] | Atlantic Aviation [Member]

Debt Disclosure [Line Items]

Undrawn portion of line of credit

302,000,000

$ 302,000,000

Borrowing capacity

$ 350,000,000

350,000,000

$ 350,000,000

$ 70,000,000

Debt instrument, term

5 years

Repayment of revolving credit facility

$ 175,000,000

Drawn on revolver credit facility

$ 200,000,000

23,000,000

Maturity

Oct. 7, 2021

Line of credit, amount outstanding

48,000,000

$ 48,000,000

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Subsequent Event [Member]

Debt Disclosure [Line Items]

Repayment of revolving credit facility

18,000,000

Line of credit, amount outstanding

30,000,000

Revolving Credit Facility [Member] | Hawaii Gas Business [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 60,000,000

60,000,000

60,000,000

$ 60,000,000

60,000,000

Debt instrument, term

5 years

Fixed portion of interest rate component

1.25%

Change in fixed margin

0.25%

Maturity

Feb. 28, 2021

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | Maximum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

1.75%

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | Minimum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

1.00%

Revolving Credit Facility [Member] | Bayonne Energy Center [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 25,000,000

25,000,000

$ 30,000,000

$ 30,000,000

$ 25,000,000

Debt instrument, term

7 years

Fixed portion of interest rate component

2.125%

Maturity

Aug. 31, 2019

Aug. 31, 2022

Revolving Credit Facility [Member] | Acquired Solar Power facility [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Borrowing capacity

20,000,000

$ 20,000,000

Revolving Credit Facility [Member] | United States- IMTT [Member]

Debt Disclosure [Line Items]

Borrowing capacity

550,000,000

$ 550,000,000

$ 550,000,000

Fixed portion of interest rate component

1.50%

Repayment of revolving credit facility

$ 76,000,000

Drawn on revolver credit facility

$ 108,000,000

Maturity

May 31, 2020

Line of credit, amount outstanding

32,000,000

$ 32,000,000

Revolving Credit Facility [Member] | United States- IMTT [Member] | Subsequent Event [Member]

Debt Disclosure [Line Items]

Repayment of revolving credit facility

8,000,000

Line of credit, amount outstanding

$ 24,000,000

Revolving Credit Facility [Member] | Canada- IMTT [Member]

Debt Disclosure [Line Items]

Borrowing capacity

50,000,000

50,000,000

$ 50,000,000

Fixed portion of interest rate component

1.50%

Maturity

May 31, 2020

Term Loan Facility [Member] | Atlantic Aviation [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 595,900,000

Borrowing capacity

$ 400,000,000

400,000,000

$ 400,000,000

$ 100,000,000

Debt instrument, term

5 years

Maturity

Oct. 7, 2021

Oct. 7, 2021

Term Loan Facility [Member] | Atlantic Aviation [Member] | Maximum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

2.25%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Minimum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

1.50%

Term Loan Facility [Member] | Hawaii Gas Business [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 80,000,000

80,000,000

$ 80,000,000

$ 80,000,000

$ 80,000,000

$ 80,000,000

Debt instrument, term

5 years

Fixed portion of interest rate component

1.75%

Change in fixed margin

0.50%

Maturity

Feb. 28, 2021

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Maximum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

1.75%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Minimum [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

1.00%

Term Loan Facility [Member] | Design-build Mechanical Contractor Business [Member] | MIC Hawaii [Member]

Debt Disclosure [Line Items]

Current and long-term debt

3,200,000

$ 3,200,000

Amortizing term loan debt assumed

$ 3,400,000

Term Loan Facility [Member] | Wind Power Generation Facilities [Member]

Debt Disclosure [Line Items]

Fixed portion of interest rate component

2.75%

1.625%

1.625%

Change in fixed margin

0.25%

Maturity

Dec. 1, 2027

Dec. 1, 2027

Term Loan Facility [Member] | Bayonne Energy Center [Member]

Debt Disclosure [Line Items]

Current and long-term debt

261,000,000

$ 261,000,000

Borrowing capacity

$ 275,000,000

275,000,000

$ 275,000,000

Debt instrument, term

7 years

Fixed portion of interest rate component

2.125%

Maturity

Aug. 31, 2021

Aug. 31, 2022

Term Loan Facility [Member] | Solar Power Facilities [Member] | MIC Hawaii [Member]

Debt Disclosure [Line Items]

Current and long-term debt

17,500,000

$ 17,500,000

Borrowing capacity

$ 18,000,000

Debt instrument, term

10 years

Fixed portion of interest rate component

2.00%

Term Loan Facility [Member] | Solar Power Facilities [Member] | Contracted Power [Member] | Floating rate term loan facility [Member]

Debt Disclosure [Line Items]

Amortizing term loan debt assumed

$ 8,500,000

$ 8,500,000

Term Loan Facility [Member] | Solar and wind power facilities [Member] | Maximum [Member]

Debt Disclosure [Line Items]

Interest Rate

5.60%

5.60%

Maturity

Dec. 1, 2036

Term Loan Facility [Member] | Solar and wind power facilities [Member] | Minimum [Member]

Debt Disclosure [Line Items]

Interest Rate

4.00%

4.00%

Maturity

Sep. 1, 2023

Term Loan Facility [Member] | Solar and wind power facilities [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 343,900,000

$ 343,900,000

Weighted average interest rate

4.75%

4.75%

Term Loan Facility [Member] | Acquired Solar Power facility [Member] | Contracted Power [Member]

Debt Disclosure [Line Items]

Amortizing term loan debt assumed

$ 73,100,000

$ 73,100,000

Tax Exempt Bonds [Member] | IMTT [Member]

Debt Disclosure [Line Items]

Current and long-term debt

509,000,000

Interest Rate Swap [Member] | IMTT [Member]

Debt Disclosure [Line Items]

Notional amount of derivative

$ 361,100,000

Fixed interest rate

1.677%

Derivative, Term of Contract

6 years

Derivatives, expiration date

Jun. 1, 2021

Interest Rate Swap [Member] | Wind Power Generation Facilities [Member] | Contracted Power [Member] | Floating rate term loan facility [Member]

Debt Disclosure [Line Items]

Current and long-term debt

$ 142,200,000

$ 142,200,000

Interest Rate Swap [Member] | Term Loan Facility [Member] | Hawaii Gas Business [Member]

Debt Disclosure [Line Items]

Notional amount of derivative

$ 80,000,000

Fixed interest rate

0.99%

0.99%

Derivatives, expiration date

Feb. 8, 2020

Feb. 8, 2020

Weighted average interest rate

2.74%

2.74%

Interest Rate Swap [Member] | Term Loan Facility [Member] | Wind Power Generation Facilities [Member]

Debt Disclosure [Line Items]

Weighted average interest rate

4.759%

4.759%

Interest Rate Swap [Member] | Term Loan Facility [Member] | Bayonne Energy Center [Member]

Debt Disclosure [Line Items]

Notional amount of derivative

$ 275,000,000

Fixed interest rate

1.786%

3.455%

3.455%

Derivative, Term of Contract

6 years

Derivatives, expiration date

Aug. 31, 2021

Interest Rate Swap [Member] | Term Loan Facility [Member] | Solar Power Facilities [Member] | MIC Hawaii [Member]

Debt Disclosure [Line Items]

Derivatives, expiration date

Jun. 30, 2026

Weighted average interest rate

3.38%

3.38%

Interest Rate Swap [Member] | Tax Exempt Bonds [Member] | IMTT [Member]

Debt Disclosure [Line Items]

Notional amount of derivative

$ 361,100,000

Fixed interest rate

1.677%

Derivative, Term of Contract

6 years

Derivatives, expiration date

Jun. 1, 2021

Jun. 1, 2021

Convertible Senior Notes [Member] | MIC Corporate [Member]

Debt Disclosure [Line Items]

Proceeds from Convertible senior notes

392,400,000

Debt instrument, term

5 years

Conversion rate

8.9364

11.7942

Convertible senior notes

$ 350,000,000

$ 350,000,000

$ 402,500,000

$ 350,000,000

$ 52,500,000

Face value of convertible senior notes

$ 1,000

$ 1,000

Interest Rate

2.00%

2.875%

3.10%

2.875%

Conversion price | $ / shares

$ 111.90

$ 84.79

Maturity

Oct. 1, 2023

Equity component of Convertible senior notes issued in Oct 2016

$ 26,700,000

Senior Notes [Member] | Hawaii Gas Business [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 100,000,000

$ 100,000,000

Fixed portion of interest rate component

4.22%

Maturity

Aug. 31, 2022

Senior Notes [Member] | IMTT [Member] | Senior Series A Notes [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 325,000,000

Interest Rate

3.92%

Maturity

May 21, 2025

Senior Notes [Member] | IMTT [Member] | Senior Series B Notes [Member]

Debt Disclosure [Line Items]

Borrowing capacity

$ 275,000,000

Interest Rate

4.02%

Maturity

May 21, 2027

Convertible Senior Notes - July 2014 [Member] | MIC Corporate [Member]

Debt Disclosure [Line Items]

Conversion rate

12.0091

Face value of convertible senior notes

$ 1,000

Fair value of Convertible senior notes

407,000,000

$ 407,000,000

Convertible Senior Notes - October 2016 [Member] | MIC Corporate [Member]

Debt Disclosure [Line Items]

Current and long-term debt

376,800,000

375,800,000

376,800,000

Unamortized debt discount

25,700,000

25,700,000

Fair value of Convertible senior notes

$ 380,000,000

$ 380,000,000

Unamortized deferred financing costs

11,000,000

Unamortized cost for equity component of convertible notes

$ 729,000

[1]

The weighted average remaining life of the deferred financing costs at December 31, 2016 was 6.2 years.

[2]

At December 31, 2016, MIC Corporate included $376.8 million in long-term debt, net of the unamortized debt discount of $25.7 million, related to the $402.5 million convertible senior notes issued in October, 2016. See further discussions below.

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Current and long-term Debt		$ 3,123,002	$ 2,833,293
Current portion		(40,016)	(40,099)	[1]
Long-term portion		3,082,986	2,793,194
Unamortized deferred financing costs	[2]	(43,020)	(46,669)
Long-term portion less unamortized debt discount and deferred financing costs		$ 3,039,966	2,746,525	[1]
Weighted Average Remaining Life Of Deferred Financing Costs		6.2
IMTT [Member]
Debt Instrument [Line Items]
Current and long-term Debt		$ 1,140,975	1,127,223
Atlantic Aviation [Member]
Debt Instrument [Line Items]
Current and long-term Debt		449,691	604,609
Contracted Power [Member]
Debt Instrument [Line Items]
Current and long-term Debt		604,862	555,486
MIC Hawaii [Member]
Debt Instrument [Line Items]
Current and long-term Debt		200,744	180,000
MIC Corporate [Member]
Debt Instrument [Line Items]
Current and long-term Debt	[3]	726,730	$ 365,975
MIC Corporate [Member] | Convertible Senior Notes - October 2016 [Member]
Debt Instrument [Line Items]
Current and long-term Debt		376,800
Unamortized debt discount		25,700
Convertible senior notes		$ 402,500
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	The weighted average remaining life of the deferred financing costs at December 31, 2016 was 6.2 years.
[3]	At December 31, 2016, MIC Corporate included $376.8 million in long-term debt, net of the unamortized debt discount of $25.7 million, related to the $402.5 million convertible senior notes issued in October, 2016. See further discussions below.

Long-Term Debt (Schedule of Fut

Long-Term Debt (Schedule of Future Maturities of Long-Term Debt) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
2,017	$ 40,016
2,018	51,086
2,019	402,157
2,020	95,084
2,021	480,888
Thereafter	2,079,512
Total	$ 3,148,743

Long-Term Debt (Schedule of Con

Long-Term Debt (Schedule of Convertible Senior) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Unamortized deferred financing costs	[1]	$ (43,020)	$ (46,669)
Net carrying amount		3,039,966	$ 2,746,525	[2]
Convertible Senior Notes - October 2016 [Member] | MIC Corporate [Member]
Principal		402,500
Unamortized debt discount		(25,741)
Unamortized deferred financing costs		(9,934)
Net carrying amount		366,825
Equity Component		$ 26,748
[1]	The weighted average remaining life of the deferred financing costs at December 31, 2016 was 6.2 years.
[2]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Long-Term Debt (Schedule of Tot

Long-Term Debt (Schedule of Total Interest Expense Recognized) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Amortization of debt discount		$ 1,007	$ 0	$ 0
Amortization of deferred financing costs		21,041	9,075	5,376
Total interest expense	[1]	116,933	$ 123,079	$ 73,196
MIC Corporate [Member] | Convertible Senior Notes [Member] | October 2016 [Member]
Debt Instrument [Line Items]
Contractual interest expense		1,969
Amortization of debt discount		1,007
Amortization of deferred financing costs		306
Total interest expense		$ 3,282
[1]	Interest expense included losses on derivative instruments of $5.0 million, $28.5 million and $19.5 million for the years ended December 31, 2016, 2015 and 2014, respectively, of which net loss of $856,000 was reclassified from accumulated other comprehensive loss for the year ended December 31, 2014.

Long-Term Debt (Schedule of Mat

Long-Term Debt (Schedule of Material Terms) (Details) - USD ($)

Oct. 07, 2016

Feb. 10, 2016

Apr. 30, 2015

Mar. 31, 2015

Jun. 02, 2015

Dec. 31, 2015

Dec. 31, 2016

Dec. 31, 2014

Aug. 31, 2022

Oct. 31, 2016

Oct. 06, 2016

Feb. 29, 2016

Aug. 10, 2015

May 21, 2015

Jul. 31, 2014

Jan. 22, 2014

Line of Credit Facility [Line Items]

Current and long-term debt

$ 2,833,293,000

$ 3,123,002,000

Interest Rate

2.00%

IMTT [Member]

Line of Credit Facility [Line Items]

Current and long-term debt

1,127,223,000

$ 1,140,975,000

IMTT [Member] | Louisiana Public Facilities Authority Revenue Bonds, Series 2007 [Member]

Line of Credit Facility [Line Items]

Maturity

Jun. 30, 2043

Current and long-term debt

$ 50,000,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

75.00%

Tender period

May 21, 2022

IMTT [Member] | Development Board of the Parish of Ascension, Louisiana Revenue Bonds,Series 2007 [Member]

Line of Credit Facility [Line Items]

Maturity

Jun. 30, 2043

Current and long-term debt

$ 165,000,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

75.00%

Tender period

May 21, 2022

IMTT [Member] | Louisiana Public Facilities Authority Gulf Opportunity Zone Revenue Bonds, Series 2010 [Member]

Line of Credit Facility [Line Items]

Maturity

Aug. 30, 2046

Current and long-term debt

$ 85,000,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

67.00%

Tender period

May 21, 2022

IMTT [Member] | Louisiana Public Facilities Authority Revenue Bonds, Series 2010 A [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 31, 2040

Current and long-term debt

$ 90,900,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

67.00%

Tender period

May 21, 2022

IMTT [Member] | Louisiana Public Facilities Authority Revenue Bonds, Series 2010 B [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 31, 2040

Current and long-term debt

$ 81,800,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

67.00%

Tender period

May 21, 2022

IMTT [Member] | New Jersey Economic Development Authority Revenue Refunding Bonds, Series 2015 [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 31, 2027

Current and long-term debt

$ 36,300,000

Fixed portion of interest rate component

0.625%

Percentage of 30-day LIBOR

75.00%

Tender period

May 21, 2022

Atlantic Aviation [Member]

Line of Credit Facility [Line Items]

Current and long-term debt

604,609,000

$ 449,691,000

Hawaii Gas Business [Member] | Senior Notes [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 100,000,000

Maturity

Aug. 31, 2022

Fixed portion of interest rate component

4.22%

MIC Corporate [Member]

Line of Credit Facility [Line Items]

Current and long-term debt

[1]

365,975,000

$ 726,730,000

Interest Rate

2.875%

Convertible Senior Notes - October 2016 [Member] | MIC Corporate [Member]

Line of Credit Facility [Line Items]

Maturity

Oct. 31, 2023

Current and long-term debt

$ 376,800,000

Interest Rate

2.00%

Convertible senior notes

$ 402,500,000

Debt Instrument, Unamortized Discount

$ 25,700,000

Convertible Senior Notes - July 2014 [Member] | MIC Corporate [Member]

Line of Credit Facility [Line Items]

Maturity

Jul. 31, 2019

Interest Rate

2.875%

Convertible senior notes

$ 350,000,000

Term Loan Facility [Member] | Atlantic Aviation [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 400,000,000

$ 400,000,000

$ 100,000,000

Maturity

Oct. 7, 2021

Oct. 7, 2021

Current and long-term debt

$ 595,900,000

Mandatory prepayment - dollar threshold of net proceeds from the sale of assets that are not reinvested

$ 10,000,000

Mandatory prepayment - dollar threshold of insurance proceeds

$ 5,000,000

Term Loan Facility [Member] | Atlantic Aviation [Member] | First Year [Member]

Line of Credit Facility [Line Items]

Amortization

2.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Next Two Years [Member]

Line of Credit Facility [Line Items]

Amortization

5.00%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Until Maturity [Member]

Line of Credit Facility [Line Items]

Amortization

7.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Minimum [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Minimum [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

2.25%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Maximum [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

2.25%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Maximum [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.25%

Term Loan Facility [Member] | Hawaii Gas Business [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 80,000,000

80,000,000

$ 80,000,000

$ 80,000,000

Maturity

Feb. 28, 2021

Fixed portion of interest rate component

1.75%

Change in fixed margin

0.50%

Number of extensions

2

Duration of extensions

1 year

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.75%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.75%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.00%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.75%

Term Loan Facility [Member] | Federal Funds Rate [Member] | Atlantic Aviation [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.50%

Term Loan Facility [Member] | Federal Funds Rate [Member] | Hawaii Gas Business [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.50%

Term Loan Facility [Member] | One-month LIBOR [Member] | Atlantic Aviation [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.00%

Revolving Credit Facility [Member] | United States- IMTT [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 550,000,000

$ 550,000,000

Maturity

May 31, 2020

Fixed portion of interest rate component

1.50%

Interest rate and fees, commitment fee percentage

0.225%

Line of credit, amount outstanding

$ 32,000,000

Revolving Credit Facility [Member] | Canada- IMTT [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 50,000,000

$ 50,000,000

Maturity

May 31, 2020

Fixed portion of interest rate component

1.50%

Interest rate and fees, commitment fee percentage

0.225%

Revolving Credit Facility [Member] | Atlantic Aviation [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 350,000,000

$ 350,000,000

$ 70,000,000

Maturity

Oct. 7, 2021

Line of credit, amount outstanding

$ 48,000,000

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Interest rate and fees, commitment fee percentage

0.25%

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Minimum [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.50%

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Minimum [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.50%

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Interest rate and fees, commitment fee percentage

0.35%

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Maximum [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

2.25%

Revolving Credit Facility [Member] | Atlantic Aviation [Member] | Maximum [Member] | Alternate Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.25%

Revolving Credit Facility [Member] | Hawaii Gas Business [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 60,000,000

60,000,000

$ 60,000,000

Maturity

Feb. 28, 2021

Fixed portion of interest rate component

1.25%

Interest rate and fees, commitment fee percentage

0.225%

Change in fixed margin

0.25%

Number of extensions

2

Duration of extensions

1 year

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | Base Rate [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.25%

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | LIBOR [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.25%

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.00%

Revolving Credit Facility [Member] | Hawaii Gas Business [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

1.75%

Revolving Credit Facility [Member] | MIC Corporate [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 410,000,000

$ 410,000,000

$ 250,000,000

Maturity

Jul. 31, 2019

Fixed portion of interest rate component

1.75%

Interest rate and fees, commitment fee percentage

0.275%

Revolving Credit Facility [Member] | Federal Funds Rate [Member] | Hawaii Gas Business [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

0.50%

Bayonne Energy Center [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

4.00%

Bayonne Energy Center [Member] | Term Loan Facility [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 275,000,000

$ 275,000,000

Maturity

Aug. 31, 2021

Aug. 31, 2022

Current and long-term debt

$ 261,000,000

Annual payment

$ 10,000,000

Fixed portion of interest rate component

2.125%

Bayonne Energy Center [Member] | Term Loan Facility [Member] | Future Scheduled Step-up [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

2.375%

Bayonne Energy Center [Member] | Revolving Credit Facility [Member]

Line of Credit Facility [Line Items]

Borrowing capacity

$ 30,000,000

$ 25,000,000

$ 25,000,000

Maturity

Aug. 31, 2019

Aug. 31, 2022

Fixed portion of interest rate component

2.125%

Interest rate and fees, commitment fee percentage

0.50%

Bayonne Energy Center [Member] | Revolving Credit Facility [Member] | Future Scheduled Step-up [Member]

Line of Credit Facility [Line Items]

Fixed portion of interest rate component

2.375%

Solar Power Generation Facilities [Member] | Term Loan Facility [Member]

Line of Credit Facility [Line Items]

Current and long-term debt

$ 201,700,000

Fixed portion of interest rate component

2.00%

Solar Power Generation Facilities [Member] | Term Loan Facility [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Maturity

Sep. 1, 2023

Mandatory prepayment - dollar threshold of net proceeds from the sale of assets that are not reinvested

$ 250,000

Mandatory prepayment - dollar threshold of insurance proceeds

250,000

Mandatory prepayment - dollar threshold of condemnation proceeds

$ 250,000

Solar Power Generation Facilities [Member] | Term Loan Facility [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 1, 2036

Mandatory prepayment - dollar threshold of net proceeds from the sale of assets that are not reinvested

$ 500,000

Mandatory prepayment - dollar threshold of insurance proceeds

1,000,000

Mandatory prepayment - dollar threshold of condemnation proceeds

$ 1,000,000

Wind Power Generation Facilities [Member] | Term Loan Facility [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 1, 2027

Dec. 1, 2027

Fixed portion of interest rate component

2.75%

1.625%

1.625%

Mandatory prepayment - dollar threshold of net proceeds from the sale of assets that are not reinvested

$ 500,000

Mandatory prepayment - dollar threshold of Guaranteed Performance commitment

250,000

Mandatory prepayment - dollar threshold of insurance proceeds

$ 10,000,000

Effective period of change in fixed margin

5 years

Change in fixed margin

0.25%

Senior Series B Notes [Member] | IMTT [Member] | Senior Notes [Member]

Line of Credit Facility [Line Items]

Maturity

May 31, 2027

Current and long-term debt

$ 275,000,000

Interest Rate

4.02%

Senior Series A Notes [Member] | IMTT [Member] | Senior Notes [Member]

Line of Credit Facility [Line Items]

Maturity

May 31, 2025

Current and long-term debt

$ 325,000,000

Interest Rate

3.92%

Solar and wind power facilities [Member] | Term Loan Facility [Member] | Minimum [Member]

Line of Credit Facility [Line Items]

Maturity

Sep. 1, 2023

Interest Rate

4.00%

Solar and wind power facilities [Member] | Term Loan Facility [Member] | Maximum [Member]

Line of Credit Facility [Line Items]

Maturity

Dec. 1, 2036

Interest Rate

5.60%

Wind Facilities [Member] | Term Loan Facility [Member]

Line of Credit Facility [Line Items]

Current and long-term debt

$ 142,200,000

[1]

At December 31, 2016, MIC Corporate included $376.8 million in long-term debt, net of the unamortized debt discount of $25.7 million, related to the $402.5 million convertible senior notes issued in October, 2016. See further discussions below.

Derivative Instruments and He61

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Thousands

Oct. 07, 2016

Feb. 10, 2016

Aug. 10, 2015

Jun. 03, 2015

Oct. 21, 2016

Jul. 31, 2016

Jul. 31, 2015

May 31, 2015

May 21, 2015

Apr. 30, 2015

Mar. 31, 2015

Mar. 31, 2015

Jun. 02, 2015

Dec. 31, 2015

Dec. 31, 2016

Dec. 31, 2014

Oct. 06, 2016

Feb. 29, 2016

Jan. 22, 2014

Derivative [Line Items]

Current and long-term debt

$ 2,833,293

$ 3,123,002

Fixed rate debt

1,200,000

1,600,000

Unhedged debt

16,000

88,400

Interest Rate Contracts [Member]

Derivative [Line Items]

Debt economically hedged with interest rate contracts

1,600,000

1,400,000

IMTT [Member]

Derivative [Line Items]

Current and long-term debt

1,127,223

1,140,975

IMTT [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Notional amount of derivative

$ 361,100

Fixed interest rate

1.677%

Derivatives, expiration date

Jun. 1, 2021

Derivative, Term of Contract

6 years

Atlantic Aviation [Member]

Derivative [Line Items]

Current and long-term debt

604,609

449,691

Term Loan Facility [Member] | Atlantic Aviation [Member]

Derivative [Line Items]

Current and long-term debt

$ 595,900

Borrowing capacity

$ 400,000

$ 400,000

$ 100,000

Debt instrument, term

5 years

Maturity

Oct. 7, 2021

Oct. 7, 2021

Term Loan Facility [Member] | Atlantic Aviation [Member] | First Year [Member]

Derivative [Line Items]

Amortization

2.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Next Two Years [Member]

Derivative [Line Items]

Amortization

5.00%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Until Maturity [Member]

Derivative [Line Items]

Amortization

7.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Maximum [Member]

Derivative [Line Items]

Fixed portion of interest rate component

2.25%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Minimum [Member]

Derivative [Line Items]

Fixed portion of interest rate component

1.50%

Term Loan Facility [Member] | Atlantic Aviation [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Payment on early termination of interest rate swap agreement

$ 17,800

Term Loan Facility [Member] | Atlantic Aviation [Member] | Interest Rate Cap [Member]

Derivative [Line Items]

Notional amount of derivative

$ 400,000

Derivatives, expiration date

Sep. 30, 2021

Derivative, Cap Interest Rate

1.00%

Derivative, Upfront premium

$ 8,600

Term Loan Facility [Member] | Hawaii Gas Business [Member]

Derivative [Line Items]

Fixed portion of interest rate component

1.75%

Borrowing capacity

$ 80,000

$ 80,000

$ 80,000

$ 80,000

Debt instrument, term

5 years

Maturity

Feb. 28, 2021

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Maximum [Member]

Derivative [Line Items]

Fixed portion of interest rate component

1.75%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Minimum [Member]

Derivative [Line Items]

Fixed portion of interest rate component

1.00%

Term Loan Facility [Member] | Hawaii Gas Business [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Notional amount of derivative

$ 80,000

Fixed interest rate

0.99%

Weighted average interest rate

2.74%

Derivatives, expiration date

Feb. 8, 2020

Feb. 8, 2020

Tax-exempt bonds [Member] | IMTT [Member]

Derivative [Line Items]

Current and long-term debt

$ 509,000

Tax-exempt bonds [Member] | IMTT [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Notional amount of derivative

$ 361,100

Fixed interest rate

1.677%

Derivatives, expiration date

Jun. 1, 2021

Jun. 1, 2021

Derivative, Term of Contract

6 years

Payment on early termination of interest rate swap agreement

$ 31,400

2014 wind power generation facilities [Member]

Derivative [Line Items]

Amortizing term loan debt assumed

$ 163,900

Bayonne Energy Center [Member]

Derivative [Line Items]

Amortizing term loan debt assumed

$ 509,100

$ 509,100

Fixed portion of interest rate component

4.00%

Variable term loan Interest rate floor

1.00%

Bayonne Energy Center [Member] | Term Loan Facility [Member]

Derivative [Line Items]

Current and long-term debt

$ 261,000

Fixed portion of interest rate component

2.125%

Borrowing capacity

$ 275,000

$ 275,000

Debt instrument, term

7 years

Maturity

Aug. 31, 2021

Aug. 31, 2022

Bayonne Energy Center [Member] | Term Loan Facility [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Fair value of derivative instruments

$ 21,500

$ 21,500

Notional amount of derivative

$ 275,000

Fixed interest rate

1.786%

3.455%

3.455%

Derivatives, expiration date

Aug. 31, 2021

Derivative, Term of Contract

6 years

Payment on early termination of interest rate swap agreement

$ 19,200

Wind Power Generation Facilities [Member] | Term Loan Facility [Member]

Derivative [Line Items]

Fixed portion of interest rate component

2.75%

1.625%

1.625%

Maturity

Dec. 1, 2027

Dec. 1, 2027

Wind Power Generation Facilities [Member] | Term Loan Facility [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Change in fixed interest rate

0.20%

Weighted average interest rate

4.759%

Solar Power Facilities [Member] | Term Loan Facility [Member] | MIC Hawaii [Member]

Derivative [Line Items]

Fixed portion of interest rate component

2.00%

Borrowing capacity

$ 18,000

Debt instrument, term

10 years

Solar Power Facilities [Member] | Term Loan Facility [Member] | MIC Hawaii [Member] | Interest Rate Swaps [Member]

Derivative [Line Items]

Notional amount of derivative

$ 18,000

Weighted average interest rate

3.38%

Derivative Instruments and He62

Derivative Instruments and Hedging Activities (Schedule of Fair Value of Derivative Instruments) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments - current assets	[1]	$ 5,514	$ 0	[2]
Fair value of derivative instruments - noncurrent assets	[1]	30,781	1,810	[2]
Total derivative contracts - assets	[1]	36,295	1,810
Fair value of derivative instruments - current liabilities	[1]	(9,297)	(19,628)	[2]
Fair value of derivative instruments - noncurrent liabilities	[1]	(5,966)	(15,698)	[2]
Total derivative contracts - liabilities	[1]	$ (15,263)	$ (35,326)
[1]	Fair value measurements at reporting date were made using significant other observable inputs (level 2).
[2]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Derivative Instruments and He63

Derivative Instruments and Hedging Activities (Schedule of Location of Hedging Activities) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative instruments		$ 8,931	$ (34,912)	$ (22,596)
Net loss in accumulated other comprehensive income reclassifications for cash flow hedges				(856)
Interest Expense [Member] | Interest Rate Cap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative instruments		8,124	0	(1)
Interest Expense [Member] | Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative instruments	[1]	(13,107)	(28,454)	(19,483)
Amount of derivative Gain/(Loss) Recognized in Interest Expense				(18,600)
Net loss in accumulated other comprehensive income reclassifications for cash flow hedges				(856)
Cost of product sales [Member] | Commodity swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative instruments		13,914	(6,458)	(571)
Other income (expense), net [Member] | Commodity swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on derivative instruments		$ 0	$ 0	$ (2,541)
[1]	Interest expense for the year ended December 31, 2014 includes $18.6 million of derivative losses and $856,000 for amounts reclassified from accumulated other comprehensive loss for the interest rate swap contracts.

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) $ / shares in Units, $ in Thousands	Mar. 12, 2015USD ($)shares	Mar. 02, 2015shares	Jul. 15, 2014USD ($)shares	May 21, 2015USD ($)$ / sharesshares	Mar. 31, 2015shares	Jul. 31, 2014shares	Dec. 31, 2016USD ($)$ / sharesshares		Dec. 31, 2015USD ($)$ / sharesshares		Dec. 31, 2014USD ($)shares		Dec. 31, 2016$ / sharesshares	Feb. 17, 2017$ / shares	May 18, 2016shares	Jun. 24, 2015USD ($)$ / shares
Shares Activity [Line Items]
Equity offering, shares					6,109,375	11,500,000
Conversion of LLC interests to common stock | $				$ 79			$ 0	[1]	$ 79	[1]	$ 0	[1]
Shares, authorized							500,000,000		500,000,000				500,000,000
Common stock, value per share | $ / shares				$ 0.001			$ 0.001		$ 0.001				$ 0.001	$ 0.001
Special stock, authorized							100						100
Special stock, par value per share | $ / shares							$ 0.001						$ 0.001
Preferred stock, authorized							100,000,000						100,000,000
Preferred stock, par value per share | $ / shares							$ 0.001						$ 0.001
Shares, issued							82,047,526		80,006,744				82,047,526
Shares, outstanding							82,047,526		80,006,744				82,047,526
Special stock, issued							100						100
Special stock, outstanding							100						100
Preferred stock, issued							0						0
Preferred stock, outstanding							0						0
Shares, authorized under Dividend Reinvestment Plan							1,000,000						1,000,000
Shares, unissued under Dividend Reinvestment Plan							935,101						935,101
Common Stock Voting Rights Shares							1						1
2014 Independent Director Equity Plan [Member]
Shares Activity [Line Items]
Shares available for grant							281,745						281,745
2014 Independent Director Equity Plan [Member] | Maximum [Member]
Shares Activity [Line Items]
Shares authorized under 2014 Independent Director Equity Plan											300,000
Fair Value of awards granted | $											$ 350
Omnibus Employee Incentive Plan 2016 [Member]
Shares Activity [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized															500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number							0						0
At the Market [Member]
Shares Activity [Line Items]
Equity offering, shares													153,692
Proceeds from equity offering | $							$ 12,600
Common stock, value per share | $ / shares																$ 0.001
At the Market [Member] | Maximum [Member]
Shares Activity [Line Items]
Aggregate gross offering price | $																$ 400,000
MIC Corporate [Member]
Shares Activity [Line Items]
Equity offering, shares		5,312,500	10,000,000
Proceeds from equity offering | $	$ 471,600		$ 739,200
MIC Corporate [Member] | Over Allotment Option [Member]
Shares Activity [Line Items]
Equity offering, shares	796,875		1,500,000
Macquarie Infrastructure Management (USA) Inc. [Member]
Shares Activity [Line Items]
Special stock, issued				100
Special Stock [Member] | Macquarie Infrastructure Management (USA) Inc. [Member]
Shares Activity [Line Items]
Right to appoint number of directors				1
Common Stock [Member]
Shares Activity [Line Items]
Shares issued per LLC interest				1
[1]	See Note 9, “Stockholders’ Equity”, for discussion on LLC interests, common stock and additional paid in capital.

Stockholders' Equity (Schedule

Stockholders' Equity (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Jul. 16, 2014	Jul. 15, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			$ 3,202,442	[1]	$ 2,970,168
Reclassification of realized losses of derivatives into earnings	[2]		0		0		$ (636)
Change in post-retirement benefit plan	[3]		2,017		(4,049)		10,816
Translation adjustment	[4],[5]		2,375		(9,671)		(4,813)
Balance			3,147,534		3,202,442	[1]	2,970,168
Net loss in accumulated other comprehensive income reclassifications for cash flow hedges							(856)
Reclassification of realized losses of derivatives into earnings, taxes							340
Loss in accumulated other comprehensive income reclassifications for cash flow hedges from unconsolidated business							(185)
Reclassification of realized losses of derivatives into earnings from unconsolidated business, taxes							65
Change in post-retirement benefit plans, taxes			1,400		(2,700)		6,900
Translation adjustment, taxes			$ (618)		$ 3,900		2,700
Equity interest acquired								50.00%
IMTT [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Translation adjustment							(66)
Loss in accumulated other comprehensive income reclassifications for cash flow hedges from unconsolidated business							(162)
Reclassification of realized losses of derivatives into earnings from unconsolidated business, taxes							57
Change in post-retirement benefit plans, amount written off							6,500
Change in post-retirement benefit plans, taxes							(2,300)
Translation adjustment, taxes							$ 23
Equity interest acquired									50.00%
IMTT [Member] | Quebec Marine Terminal [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Equity interest acquired		33.30%
Cash Flow Hedges, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	[6]		$ 0		$ 0		$ (636)
Reclassification of realized losses of derivatives into earnings	[6]						636
Change in post-retirement benefit plan	[6]		0		0		0
Translation adjustment	[6]		0		0		0
Purchase of noncontrolling interest in Subsidiary	[6],[7]		0
Balance	[6]		0		0		0
Post-Retirement Benefit Plans, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	[8]		(14,788)		(18,837)		(8,021)
Reclassification of realized losses of derivatives into earnings	[8]						0
Change in post-retirement benefit plan	[8]		(2,017)		4,049		(10,816)
Translation adjustment	[8]		0		0		0
Purchase of noncontrolling interest in Subsidiary	[7],[8]		0
Balance	[8]		(16,805)		(14,788)		(18,837)
Translation Adjustment, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	[9]		(14,530)		(4,859)		(46)
Reclassification of realized losses of derivatives into earnings	[9]						0
Change in post-retirement benefit plan	[9]		0		0		0
Translation adjustment	[9]		2,375		(9,671)		(4,813)
Purchase of noncontrolling interest in Subsidiary	[7],[9]		0
Balance	[9]		(12,155)		(14,530)		(4,859)
Total Accumulated Other Comprehensive Loss, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			(29,318)		(23,696)		(8,703)
Reclassification of realized losses of derivatives into earnings							636
Change in post-retirement benefit plan			(2,017)		4,049		(10,816)
Translation adjustment			2,375		(9,671)		(4,813)
Purchase of noncontrolling interest in Subsidiary	[7]		0
Balance			(28,960)		(29,318)		(23,696)
Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			6,023		2,146		258
Reclassification of realized losses of derivatives into earnings							(258)
Change in post-retirement benefit plan			0		0		0
Translation adjustment			(1,434)		3,877		2,146
Purchase of noncontrolling interest in Subsidiary	[7]		(4,589)
Balance			0		6,023		2,146
Accumulated Other Comprehensive Loss Attributable to Noncontrolling Interest [Member] | IMTT [Member] | Quebec Marine Terminal [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Purchase of noncontrolling interest in Subsidiary		$ (4,600)
Total Stockholders' Accumulated Other Comprehensive Loss, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			(23,295)		(21,550)		(8,445)
Reclassification of realized losses of derivatives into earnings							378
Change in post-retirement benefit plan			(2,017)		4,049		(10,816)
Translation adjustment			941		(5,794)		(2,667)
Purchase of noncontrolling interest in Subsidiary	[7]		(4,589)
Balance			$ (28,960)		$ (23,295)		$ (21,550)
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	Reclassification of realized losses of derivatives is composed of (i) pre-tax derivative losses into interest expense of $856,000 and the related tax benefit of $340,000 in the consolidated statements of operations; and (ii) pre-tax derivative losses of $185,000 as an adjustment to investment in unconsolidated business and an adjustment to deferred taxes of $65,000, in the consolidated balance sheet for the year ended December 31, 2014. See Note 9, “Stockholders’ Equity”, for further discussions.
[3]	Change in post-retirement benefit plans is presented net of tax benefit of $1.4 million, tax expense of $2.7 million and tax benefit of $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively. See Note 9, “Stockholders’ Equity”, for further discussions.
[4]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss. See Note 9, “Stockholders’ Equity”, for disclosures on accumulated other comprehensive loss.
[5]	Translation adjustment is presented net of tax expense of $618,000 and tax benefits of $3.9 million and $2.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. See Note 9, “Stockholders’ Equity”, for further discussions.
[6]	Reclassification of realized losses of derivatives is composed of (i) pre-tax derivative losses into interest expense of $856,000 and the related tax benefit of $340,000 in the consolidated statements of operations; and (ii) pre-tax derivative losses of $185,000 as an adjustment to investment in unconsolidated business, and an adjustment to deferred taxes of $65,000, in the consolidated balance sheet for the year ended December 31, 2014. For the year ended December 31, 2014, the Company wrote-off $162,000 for the amount related to the investment in unconsolidated business and related taxes of $57,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations.
[7]	On March 31, 2016, IMTT acquired the remaining 33.3% interest in its Quebec terminal that it did not previously own. As part of this transaction, the translation adjustment of $4.6 million, net of taxes, was reclassified from noncontrolling interests to accumulated other comprehensive loss.
[8]	Change in post-retirement benefit plans is presented net of tax benefit of $1.4 million, tax expense of $2.7 million and tax benefit of $6.9 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, change in post-retirement benefit plans also includes a write-off of the remaining balance of $6.5 million and the related taxes of $2.3 million, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations.
[9]	Translation adjustment is presented net of tax expense of $618,000 and tax benefits of $3.9 million and $2.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. For the year ended December 31, 2014, translation adjustment also includes a write-off of the remaining balance of $66,000 and the related taxes of $23,000, previously accounted for under the equity method of accounting in conjunction with the IMTT Acquisition. This write-off is recorded in gain from acquisition/divestiture of businesses in the consolidated statement of operations.

Stockholders' Equity (Schedul66

Stockholders' Equity (Schedule of Dividends) (Details)	12 Months Ended
	Dec. 31, 2016$ / shares
Dividend One [Member]
Dividends Payable [Line Items]
Declared	Feb. 18, 2014
Period Covered	Fourth quarter 2013
$ per Share	$ 0.9125
Record Date	Mar. 3, 2014
Payable Date	Mar. 6, 2014
Dividend Two [Member]
Dividends Payable [Line Items]
Declared	Apr. 28, 2014
Period Covered	First quarter 2014
$ per Share	$ 0.9375
Record Date	May 12, 2014
Payable Date	May 15, 2014
Dividend Three [Member]
Dividends Payable [Line Items]
Declared	Jul. 3, 2014
Period Covered	Second quarter 2014
$ per Share	$ 0.95
Record Date	Aug. 11, 2014
Payable Date	Aug. 14, 2014
Dividend Four [Member]
Dividends Payable [Line Items]
Declared	Oct. 27, 2014
Period Covered	Third quarter 2014
$ per Share	$ 0.98
Record Date	Nov. 10, 2014
Payable Date	Nov. 13, 2014
Dividend Five [Member]
Dividends Payable [Line Items]
Declared	Feb. 17, 2015
Period Covered	Fourth quarter 2014
$ per Share	$ 1.02
Record Date	Mar. 2, 2015
Payable Date	Mar. 5, 2015
Dividend Six [Member]
Dividends Payable [Line Items]
Declared	Apr. 30, 2015
Period Covered	First quarter 2015
$ per Share	$ 1.07
Record Date	May 14, 2015
Payable Date	May 19, 2015
Dividend Seven [Member]
Dividends Payable [Line Items]
Declared	Jul. 30, 2015
Period Covered	Second quarter 2015
$ per Share	$ 1.11
Record Date	Aug. 13, 2015
Payable Date	Aug. 18, 2015
Dividend Eight [Member]
Dividends Payable [Line Items]
Declared	Oct. 29, 2015
Period Covered	Third quarter 2015
$ per Share	$ 1.13
Record Date	Nov. 13, 2015
Payable Date	Nov. 18, 2015
Dividend Nine [Member]
Dividends Payable [Line Items]
Declared	Feb. 18, 2016
Period Covered	Fourth quarter 2015
$ per Share	$ 1.15
Record Date	Mar. 3, 2016
Payable Date	Mar. 8, 2016
Dividend Ten [Member]
Dividends Payable [Line Items]
Declared	Apr. 28, 2016
Period Covered	First quarter 2016
$ per Share	$ 1.20
Record Date	May 12, 2016
Payable Date	May 17, 2016
Dividend Eleven [Member]
Dividends Payable [Line Items]
Declared	Jul. 28, 2016
Period Covered	Second quarter 2016
$ per Share	$ 1.25
Record Date	Aug. 11, 2016
Payable Date	Aug. 16, 2016
Dividend Twelve [Member]
Dividends Payable [Line Items]
Declared	Oct. 27, 2016
Period Covered	Third quarter 2016
$ per Share	$ 1.29
Record Date	Nov. 10, 2016
Payable Date	Nov. 15, 2016
Dividend Thirteen [Member]
Dividends Payable [Line Items]
Declared	Feb. 17, 2017
Period Covered	Fourth quarter 2016
$ per Share	$ 1.31
Record Date	Mar. 3, 2017
Payable Date	Mar. 8, 2017

Stockholders' Equity (Schedul67

Stockholders' Equity (Schedule of Stock Issued to Board of Directors) (Details) - $ / shares		1 Months Ended	12 Months Ended
		Sep. 30, 2016	Dec. 31, 2016
Director [Member]
Share-based Goods and Nonemployee Services Transaction [Line Items]
Restricted stock, net of forfeitures		(2,151)
Range One [Member]
Share-based Goods and Nonemployee Services Transaction [Line Items]
Date of Grant			May 21, 2014
Stock Units Granted	[1]		12,525
Price of Stock Units Granted			$ 59.89
Date of Vesting			May 19, 2015
Range Two [Member]
Share-based Goods and Nonemployee Services Transaction [Line Items]
Date of Grant	[2]		Jun. 18, 2015
Stock Units Granted	[1],[2]		8,660
Price of Stock Units Granted	[2]		$ 86.61
Date of Vesting	[2]		May 17, 2016
Range Three [Member]
Share-based Goods and Nonemployee Services Transaction [Line Items]
Date of Grant	[2],[3]		May 18, 2016
Stock Units Granted	[1],[2],[3]		8,604
Price of Stock Units Granted	[2],[3]		$ 69.72
Date of Vesting	[2],[3],[4]
Range Four [Member]
Share-based Goods and Nonemployee Services Transaction [Line Items]
Date of Grant	[2],[5]		Nov. 1, 2016
Stock Units Granted	[1],[2],[5]		991
Price of Stock Units Granted	[2],[5]		$ 81.93
Date of Vesting	[2],[4],[5]
[1]	Stock units granted refer (i) from and after the time of the Conversion, to common stock and (ii) prior to the Conversion, LLC interests.
[2]	Restricted stock units granted under the 2014 Plan.
[3]	Restricted stock units are net of forfeitures of 2,151 restricted stock units due to the retirement of an independent director on September 30, 2016.
[4]	Date of vesting will be the day immediately preceding the 2017 annual meeting of the Company's stockholders.
[5]	Represents additional restricted stock unit grants to a new independent director.

Reportable Segments (Narrative)

Reportable Segments (Narrative) (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jul. 15, 2014USD ($)	Dec. 31, 2016USD ($)ItemMW	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Mar. 31, 2015MW	Jul. 16, 2014
Segment Reporting Information [Line Items]
Number of reportable segments		4
Equity in earnings and amortization charges of investee | $		$ 0	$ 0	$ 26,391
Tax rate used to calculate net income attributable to MIC				35.00%
Equity interest acquired						50.00%
Number of solar projects		7
Maximum [Member]
Segment Reporting Information [Line Items]
Life of Purchase Power Agreements		25 years
Minimum [Member]
Segment Reporting Information [Line Items]
Life of Purchase Power Agreements		20 years
Canada- IMTT [Member]
Segment Reporting Information [Line Items]
Number of marine terminals		2
Canada- IMTT [Member] | Quebec Marine Terminal [Member]
Segment Reporting Information [Line Items]
Number of marine terminals		1
Canada- IMTT [Member] | Newfoundland [Member] | Partially Owned [Member]
Segment Reporting Information [Line Items]
Number of marine terminals		1
Atlantic Aviation [Member]
Segment Reporting Information [Line Items]
Number of Airport Locations | Item		69
Contracted Power [Member]
Segment Reporting Information [Line Items]
Equity interest acquired		100.00%
Number of solar projects		6
Number of wind power facilities		2
United States- IMTT [Member]
Segment Reporting Information [Line Items]
Equity in earnings and amortization charges of investee | $	$ 26,100
Equity method ownership percentage	50.00%
Number of marine terminals		10
MIC Hawaii [Member]
Segment Reporting Information [Line Items]
Number of solar projects		2
Bayonne Energy Center [Member]
Segment Reporting Information [Line Items]
Electricity generating capacity | MW					512
Equity interest acquired					100.00%
Percentage of contracted tolling agreement					62.50%
Solar and Wind Power Facilities [Member] | Contracted Power [Member]
Segment Reporting Information [Line Items]
Electricity generating capacity | MW		340

Reportable Segments (Schedule o

Reportable Segments (Schedule of Selected Consolidated Financial Data) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Revenue	$ 1,662,451
Net income attributable to MIC	$ 77,923	[1]
[1]	The tax rate used to calculate net income attributable to MIC was 35.0%.

Reportable Segments (Schedule70

Reportable Segments (Schedule of Segment Information) (Details) - USD ($) $ in Thousands		3 Months Ended									6 Months Ended	12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jul. 15, 2014	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue		$ 437,241	$ 420,524	$ 397,579	$ 396,387	$ 401,354		$ 415,709	$ 423,689	$ 398,498		$ 1,651,731	$ 1,639,250		$ 1,350,918
Net income		72,808	$ 42,026	$ 19,192	$ 22,355	32,923		$ 10,638	$ (63,096)	$ (89,002)		156,381	(108,537)		1,042,028
Provision for income taxes	[1]											71,257	(65,161)		(24,374)
Other non-cash expenses												1,370	1,047		(5,411)
Capital expenditures paid												314,684	194,148		123,946
Property, equipment, land and leasehold improvements, net		4,346,536				4,116,163	[2]					4,346,536	4,116,163	[2]
Total assets		7,559,253				7,308,804	[2]					7,559,253	7,308,804	[2]
Pension expense												8,601	7,300		4,148
IMTT [Member]
Segment Reporting Information [Line Items]
Revenue												532,472	550,041		255,934	[3]
Net income												83,142	74,726		34,948	[3]
Interest expense, net												38,752	37,378		10,864	[3]
Provision for income taxes												(57,736)	(51,520)		(25,768)	[3]
Other non-cash expenses												(657)	(378)		(195)	[3]
EBITDA excluding non-cash items												321,891	302,067		127,751	[3]
Capital expenditures paid												96,865	96,990		47,376
Property, equipment, land and leasehold improvements, net		$ 2,218,256				$ 2,238,654						2,218,256	2,238,654
Pension expense												$ 7,219	$ 6,063		$ 3,410	[3]
IMTT [Member] | Prior to acquisition [Member]
Segment Reporting Information [Line Items]
Revenue	[4]										$ 311,533
Net income	[4]										57,725
Interest expense, net	[4]										16,375
Provision for income taxes	[4]										38,265
Depreciation and amortization											40,922
Other non-cash expenses	[4]										112
EBITDA excluding non-cash items	[4],[5]										157,424
Capital expenditures paid	[4]										59,868
Property, equipment, land and leasehold improvements, net	[4]										1,289,245
Total assets	[4]										1,415,378
Pension expense	[4]										$ 4,025
[1]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.
[2]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[3]	Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition.
[4]	Amounts represent financial position of IMTT business prior to July 16, 2014, the date of the IMTT Acquisition.
[5]	The Company defines EBITDA excluding non-cash items as net income (loss) or earnings - the most comparable GAAP measure - before interest, taxes, depreciation and amortization and non-cash items including impairments, unrealized derivative gains and losses, adjustments for other non-cash items and pension expense reflected in the statements of operations.

Reportable Segments (Schedule71

Reportable Segments (Schedule of Revenue From External Customers) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Service revenue										$ 1,288,562	$ 1,288,501	$ 1,064,682
Product revenue										363,169	350,749	284,400
Financing and equipment lease income										0	0	1,836
Total revenues		$ 437,241	$ 420,524	$ 397,579	$ 396,387	$ 401,354	$ 415,709	$ 423,689	$ 398,498	1,651,731	1,639,250	1,350,918
IMTT [Member]
Segment Reporting Information [Line Items]
Service revenue										532,472	550,041	255,934	[1]
Product revenue										0	0	0	[1]
Financing and equipment lease income	[1]											0
Total revenues										532,472	550,041	255,934	[1]
Atlantic Aviation [Member]
Segment Reporting Information [Line Items]
Service revenue										740,209	738,460	779,261
Product revenue										0	0	0
Financing and equipment lease income												0
Total revenues										740,209	738,460	779,261
Contracted Power [Member]
Segment Reporting Information [Line Items]
Service revenue										0	0	29,487
Product revenue										150,010	123,797	19,779
Financing and equipment lease income												1,836
Total revenues										150,010	123,797	51,102
MIC Hawaii [Member]
Segment Reporting Information [Line Items]
Service revenue										20,762	0	0
Product revenue										213,159	226,952	264,621
Financing and equipment lease income												0
Total revenues										233,921	$ 226,952	$ 264,621
Intersegment Revenue [Member]
Segment Reporting Information [Line Items]
Service revenue										(4,881)
Product revenue										0
Total revenues										$ (4,881)
[1]	Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition.

Reportable Segments (Schedule72

Reportable Segments (Schedule of EBITDA for Reportable Segments) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net income (loss)		$ 72,808	$ 42,026	$ 19,192	$ 22,355	$ 32,923	$ 10,638	$ (63,096)	$ (89,002)	$ 156,381	$ (108,537)	$ 1,042,028
Provision for income taxes	[1]									(71,257)	65,161	24,374
Depreciation										226,492	215,243	102,816
Amortization of intangibles										65,425	101,435	42,695
Pension expense										8,601	7,300	4,148
Other non-cash expense (income)										(1,370)	(1,047)	5,411
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net income (loss)										192,517	114,372	86,999
Interest expense, net										99,558	108,782	67,179
Provision for income taxes										132,394	86,749	64,322
Depreciation	[2]									226,492	215,243	102,816
Amortization of intangibles										65,425	101,435	42,695
Pension expense										8,601	7,300	4,148
Other non-cash expense (income)										(17,024)	42	7,202
EBITDA excluding non-cash items	[3]									707,963	633,923	375,361
IMTT [Member]
Segment Reporting Information [Line Items]
Net income (loss)										83,142	74,726	34,948	[4]
Interest expense, net										38,752	37,378	10,864	[4]
Provision for income taxes										57,736	51,520	25,768	[4]
Depreciation										123,346	120,950	47,475	[2],[4]
Amortization of intangibles										11,039	11,052	5,091	[4]
Pension expense										7,219	6,063	3,410	[4]
Other non-cash expense (income)										657	378	195	[4]
EBITDA excluding non-cash items										321,891	302,067	127,751	[4]
Atlantic Aviation [Member]
Segment Reporting Information [Line Items]
Net income (loss)										59,538	22,805	36,964
Interest expense, net										33,961	35,735	40,618
Provision for income taxes										39,889	16,081	25,096
Depreciation										41,493	40,249	28,264	[2]
Amortization of intangibles										49,166	86,102	35,514
Pension expense										110	112	114
Other non-cash expense (income)										905	2,533	1,361
EBITDA excluding non-cash items										225,062	203,617	167,931
Contracted Power [Member]
Segment Reporting Information [Line Items]
Net income (loss)										14,093	(7,152)	(6,242)
Interest expense, net										21,286	28,390	8,606
Provision for income taxes										14,328	4,887	823
Depreciation										51,120	45,490	19,132	[2]
Amortization of intangibles										4,428	3,500	843
Pension expense										0	0	0
Other non-cash expense (income)										(7,047)	(6,959)	(439)
EBITDA excluding non-cash items										98,208	68,156	22,723
MIC Hawaii [Member]
Segment Reporting Information [Line Items]
Net income (loss)										35,744	23,993	21,329
Interest expense, net										5,559	7,279	7,091
Provision for income taxes										20,441	14,261	12,635
Depreciation										10,533	8,554	7,945	[2]
Amortization of intangibles										792	781	1,247
Pension expense										1,272	1,125	624
Other non-cash expense (income)										(11,539)	4,090	6,085
EBITDA excluding non-cash items										$ 62,802	$ 60,083	$ 56,956
[1]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.
[2]	Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations.
[3]	Subsequent to July 16, 2014, the date of the IMTT Acquisition, total reportable segments' EBITDA excluding non-cash items includes the results of IMTT’s EBITDA excluding non-cash items. Prior to July 16, 2014, MIC accounted for its 50% investment in IMTT under the equity method of accounting. As such, MIC’s 50% share of IMTT’s net income was reported in equity in earnings and amortization charges of investee in the above table for periods prior to July 16, 2014.
[4]	Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition.

Reportable Segments (Schedule73

Reportable Segments (Schedule of Reconciliation of EBITDA for Reportable Segments) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Interest income		$ 132	$ 55	$ 112
Interest expense	[1]	(116,933)	(123,079)	(73,196)
Depreciation		(226,492)	(215,243)	(102,816)
Amortization of intangibles		(65,425)	(101,435)	(42,695)
Selling, general and administrative expenses - Corporate and Other		(303,033)	(304,862)	(265,254)
Fees to Manager - related party		(68,486)	(354,959)	(168,182)
Gain from acquisition/divestiture of businesses	[2]	0	0	1,027,054
Equity in earnings and amortization charges of investee		0	0	26,391
Pension expense		8,601	7,300	4,148
Other income (expense), net		21,786	1,288	(2,307)
Total consolidated net income (loss) before income taxes		226,126	(178,968)	1,014,909
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total reportable segments EBITDA excluding non-cash items	[3]	707,963	633,923	375,361
Interest income		132	55	112
Interest expense		(116,933)	(123,079)	(73,196)
Depreciation	[4]	(226,492)	(215,243)	(102,816)
Amortization of intangibles		(65,425)	(101,435)	(42,695)
Fees to Manager - related party		(68,486)	(354,959)	(168,182)
Gain from acquisition/divestiture of businesses		0	0	1,027,054
Equity in earnings and amortization charges of investee		0	0	26,391
Pension expense		8,601	7,300	4,148
Other income (expense), net		17,024	645	(7,446)
Total consolidated net income (loss) before income taxes		226,126	(178,968)	1,014,909
Total Reportable Segments [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Selling, general and administrative expenses - Corporate and Other		$ (13,056)	$ (11,575)	$ (15,526)
[1]	Interest expense included losses on derivative instruments of $5.0 million, $28.5 million and $19.5 million for the years ended December 31, 2016, 2015 and 2014, respectively, of which net loss of $856,000 was reclassified from accumulated other comprehensive loss for the year ended December 31, 2014.
[2]	Included the gain of $948.1 million from the acquisition of the remaining 50% interest in IMTT (IMTT Acquisition) from the remeasuring to fair value of the Company’s previous 50% ownership interest and the gain of $78.9 million from the sale of the Company’s interest in the district energy business.
[3]	Subsequent to July 16, 2014, the date of the IMTT Acquisition, total reportable segments' EBITDA excluding non-cash items includes the results of IMTT’s EBITDA excluding non-cash items. Prior to July 16, 2014, MIC accounted for its 50% investment in IMTT under the equity method of accounting. As such, MIC’s 50% share of IMTT’s net income was reported in equity in earnings and amortization charges of investee in the above table for periods prior to July 16, 2014.
[4]	Depreciation includes depreciation expense for the district energy business, a component of the CP segment prior to the Company’s divestiture of the business on August 21, 2014, which was reported in cost of services in the consolidated statements of operations.

Reportable Segments (Schedule74

Reportable Segments (Schedule of Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Capital expenditures	$ 314,684	$ 194,148	$ 123,946
IMTT [Member]
Segment Reporting Information [Line Items]
Capital expenditures	96,865	96,990	47,376
Atlantic Aviation [Member]
Segment Reporting Information [Line Items]
Capital expenditures	113,092	64,385	43,691
Contracted Power [Member]
Segment Reporting Information [Line Items]
Capital expenditures	69,268	15,636	14,376
MIC Hawaii [Member]
Segment Reporting Information [Line Items]
Capital expenditures	$ 35,459	$ 17,137	$ 18,503

Reportable Segments (Schedule75

Reportable Segments (Schedule of Assets of Reportable Segments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	$ 4,346,536	$ 4,116,163	[1]
Goodwill	2,024,409	2,017,211	[1]
Total Assets	7,559,253	7,308,804	[1]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	32	0
Goodwill	0	0
Total Assets	(2,109)	8,900
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	4,346,504	4,116,163
Goodwill	2,024,409	2,017,211
Total Assets	7,561,362	7,299,904
IMTT [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	2,218,256	2,238,654
Goodwill	1,411,029	1,410,668
IMTT [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Assets	3,978,379	4,000,079	[2]
Atlantic Aviation [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	465,096	390,188
Goodwill	468,419	464,722
Atlantic Aviation [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Assets	1,564,668	1,502,512	[2]
Contracted Power [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	1,383,289	1,274,557
Goodwill	21,628	21,628
Contracted Power [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Assets	1,516,602	1,411,233	[2]
MIC Hawaii [Member]
Segment Reporting Information [Line Items]
Property, Equipment, Land and Leasehold Improvements, net	279,863	212,764
Goodwill	123,333	120,193
MIC Hawaii [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Assets	$ 501,713	$ 386,080	[2]
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	Conformed to current period presentation. See Note 2, "Summary of Significant Accounting Policies", for Recently Issued Accounting Standards adopted in the year ended December 31, 2016.

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details)	Oct. 07, 2016USD ($)	Feb. 10, 2016USD ($)	Aug. 10, 2015USD ($)	Jul. 15, 2014USD ($)	Nov. 30, 2016USD ($)shares	Oct. 31, 2016USD ($)	Oct. 21, 2016USD ($)	Jul. 31, 2015USD ($)	May 31, 2015USD ($)shares	Mar. 31, 2015USD ($)shares	Oct. 31, 2014USD ($)	Aug. 31, 2014USD ($)	Jul. 31, 2014USD ($)shares	Jan. 22, 2014USD ($)	Dec. 31, 2016USD ($)$ / sharessharesbbl	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)$ / sharesshares		Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)bbl	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2016USD ($)$ / sharessharesbbl	Dec. 31, 2015USD ($)$ / sharesshares		Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)$ / sharessharesbbl	Feb. 17, 2017$ / shares	Oct. 28, 2016USD ($)	Oct. 13, 2016USD ($)	Oct. 06, 2016USD ($)	Feb. 29, 2016USD ($)	Jun. 24, 2015USD ($)$ / shares	May 21, 2015$ / sharesshares	Apr. 02, 2015USD ($)	Dec. 31, 2013USD ($)
Related Party Transaction [Line Items]
Shares sold by the Manager, a related party | shares					2,870,000				1,900,000
Proceeds from sale of shares by Manager, a related party					$ 233,800,000				$ 160,400,000
Special stock, issued | shares															100													100				100
Common stock, par value per share | $ / shares															$ 0.001				$ 0.001									$ 0.001	$ 0.001			$ 0.001	$ 0.001						$ 0.001
Equity offering, shares | shares										6,109,375			11,500,000
Debt issuance costs paid																												$ 17,392,000	$ 23,816,000		$ 15,142,000
Cash and cash equivalents															$ 44,767,000				$ 22,394,000	[1]				$ 48,014,000				$ 44,767,000	22,394,000	[1]	48,014,000	$ 44,767,000									$ 233,373,000
Performance Fee To Manager Related Party Settled In Cash								$ 67,800,000			$ 65,000,000
Number of employees															2													2				2
Revolving Credit Facility [Member] | Bayonne Energy Center [Member]
Related Party Transaction [Line Items]
Borrowing capacity			$ 25,000,000							$ 30,000,000					$ 25,000,000								$ 30,000,000					$ 25,000,000				$ 25,000,000
Debt Instrument, Term			7 years
Term Loan Facility [Member] | Bayonne Energy Center [Member]
Related Party Transaction [Line Items]
Borrowing capacity			$ 275,000,000												275,000,000													275,000,000				275,000,000
Debt Instrument, Term			7 years
Term Loan Facility [Member] | Bayonne Energy Center [Member] | Interest Rate Swaps [Member]
Related Party Transaction [Line Items]
Payment on early termination of interest rate swap agreement								19,200,000
Atlantic Aviation [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity	$ 350,000,000														350,000,000													350,000,000				350,000,000				$ 70,000,000
Debt Instrument, Term	5 years
Atlantic Aviation [Member] | Term Loan Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity	$ 400,000,000													$ 100,000,000	400,000,000													400,000,000				400,000,000
Debt Instrument, Term	5 years
Atlantic Aviation [Member] | Term Loan Facility [Member] | Interest Rate Swaps [Member]
Related Party Transaction [Line Items]
Payment on early termination of interest rate swap agreement							$ 17,800,000
MIC Corporate [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity													$ 250,000,000		410,000,000				410,000,000									410,000,000	410,000,000			410,000,000
Debt Instrument, Term													5 years
MIC Corporate [Member] | Convertible Senior Notes [Member]
Related Party Transaction [Line Items]
Convertible Debt				$ 350,000,000		$ 402,500,000							$ 350,000,000																					$ 52,500,000	$ 350,000,000
Debt Instrument, Term				5 years
Hawaii Gas Business [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity		$ 60,000,000													60,000,000				60,000,000									60,000,000	60,000,000			60,000,000
Debt Instrument, Term		5 years
Hawaii Gas Business [Member] | Term Loan Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity		$ 80,000,000													$ 80,000,000				$ 80,000,000									$ 80,000,000	$ 80,000,000			$ 80,000,000					$ 80,000,000
Debt Instrument, Term		5 years
At the Market [Member]
Related Party Transaction [Line Items]
Common stock, par value per share | $ / shares																																						$ 0.001
Equity offering, shares | shares																																153,692
At the Market [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Aggregate gross offering price																																						$ 400,000,000
Macquarie Infrastructure Management (USA) Inc. [Member]
Related Party Transaction [Line Items]
Shares of the Company held by Manager, a related party | shares															4,510,795				5,506,369									4,510,795	5,506,369			4,510,795
Base management fees to be settled/settled in shares															$ 18,916,000	$ 18,382,000	$ 16,392,000	$ 14,796,000	$ 17,009,000		$ 18,118,000	$ 18,918,000	16,545,000	14,192,000	$ 13,915,000	$ 9,535,000	$ 8,994,000	$ 68,500,000	$ 70,600,000		46,600,000
Performance fees to be settled/settled in shares and cash															$ 0	$ 0	$ 0	$ 0	0		$ 0	$ 135,641,000	$ 148,728,000	$ 0	$ 116,586,000	$ 4,960,000	$ 0		284,400,000		121,500,000
Reimbursement of out-of-pocket expenses																												$ 714,000	533,000		571,000
Special stock, issued | shares																																							100
Macquarie Infrastructure Management (USA) Inc. [Member] | Special Stock [Member]
Related Party Transaction [Line Items]
Right to appoint number of directors																																							1
MENAT [Member]
Related Party Transaction [Line Items]
Revenue from related party																													565,000
MENAT [Member] | IMTT [Member]
Related Party Transaction [Line Items]
Capacity Leased To Related Party | bbl																						154,000						1,000,000
Capacity Leased Expired To Related Party | bbl																						56,000						823,000
Revenue from related party																												$ 3,900,000
Aggregate Capacity Leased To Related Party End Of Period | bbl															298,000													298,000				298,000
MIHI LLC [Member] | Revolving Credit Facility [Member] | Bayonne Energy Center [Member]
Related Party Transaction [Line Items]
Borrowing capacity																																								$ 7,500,000
Interest costs incurred																													8,000
MIHI LLC [Member] | MIC Corporate [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity													50,000,000						50,000,000										50,000,000
Interest costs incurred																												$ 236,000	237,000		65,000
Debt issuance costs paid													250,000
MCUSA [Member] | Atlantic Aviation [Member] | Term Loan Facility [Member]
Related Party Transaction [Line Items]
Advisory fees														$ 16,000
MCUSA [Member] | District Energy [Member]
Related Party Transaction [Line Items]
Advisory fees												$ 1,600,000
MCUSA [Member] | MIC Corporate [Member] | Convertible Senior Notes [Member]
Related Party Transaction [Line Items]
Advisory fees						$ 403,000							1,100,000
MCUSA [Member] | Equity Offering [Member] | MIC Corporate [Member]
Related Party Transaction [Line Items]
Advisory fees										$ 2,300,000			$ 3,000,000
MBL [Member] | Bayonne Energy Center [Member] | Interest Rate Swaps [Member]
Related Party Transaction [Line Items]
Payment on early termination of interest rate swap agreement								$ 4,800,000
Interest costs incurred																													396,000
MBL [Member] | Atlantic Aviation [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity																																				$ 15,700,000
Interest costs incurred																												90,000	114,000		$ 107,000
Related Party Lender [Member] | Hawaii Gas Business [Member]
Related Party Transaction [Line Items]
Interest costs incurred																												222,000	156,000
Cash and cash equivalents															$ 100,000				100,000									$ 100,000	100,000			$ 100,000
Related Party Lender [Member] | Hawaii Gas Business [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity		$ 6,400,000																	8,600,000										8,600,000
Related Party Lender [Member] | Hawaii Gas Business [Member] | Term Loan Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity		$ 8,600,000																	$ 11,400,000										$ 11,400,000
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.

Related Party Transactions (Sch

Related Party Transactions (Schedule of Dividends Paid to Manager) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / shares
Dividend One [Member]
Dividends Payable [Line Items]
Declared	Feb. 18, 2014
Period Covered	Fourth quarter 2013
$ per Share | $ / shares	$ 0.9125
Record Date	Mar. 3, 2014
Payable Date	Mar. 6, 2014
Cash Paid to Manager | $	$ 2,945
Dividend Two [Member]
Dividends Payable [Line Items]
Declared	Apr. 28, 2014
Period Covered	First quarter 2014
$ per Share | $ / shares	$ 0.9375
Record Date	May 12, 2014
Payable Date	May 15, 2014
Cash Paid to Manager | $	$ 3,180
Dividend Three [Member]
Dividends Payable [Line Items]
Declared	Jul. 3, 2014
Period Covered	Second quarter 2014
$ per Share | $ / shares	$ 0.95
Record Date	Aug. 11, 2014
Payable Date	Aug. 14, 2014
Cash Paid to Manager | $	$ 3,402
Dividend Four [Member]
Dividends Payable [Line Items]
Declared	Oct. 27, 2014
Period Covered	Third quarter 2014
$ per Share | $ / shares	$ 0.98
Record Date	Nov. 10, 2014
Payable Date	Nov. 13, 2014
Cash Paid to Manager | $	$ 4,438
Dividend Five [Member]
Dividends Payable [Line Items]
Declared	Feb. 17, 2015
Period Covered	Fourth quarter 2014
$ per Share | $ / shares	$ 1.02
Record Date	Mar. 2, 2015
Payable Date	Mar. 5, 2015
Cash Paid to Manager | $	$ 4,905
Dividend Six [Member]
Dividends Payable [Line Items]
Declared	Apr. 30, 2015
Period Covered	First quarter 2015
$ per Share | $ / shares	$ 1.07
Record Date	May 14, 2015
Payable Date	May 19, 2015
Cash Paid to Manager | $	$ 7,281
Dividend Seven [Member]
Dividends Payable [Line Items]
Declared	Jul. 30, 2015
Period Covered	Second quarter 2015
$ per Share | $ / shares	$ 1.11
Record Date	Aug. 13, 2015
Payable Date	Aug. 18, 2015
Cash Paid to Manager | $	$ 5,693
Dividend Eight [Member]
Dividends Payable [Line Items]
Declared	Oct. 29, 2015
Period Covered	Third quarter 2015
$ per Share | $ / shares	$ 1.13
Record Date	Nov. 13, 2015
Payable Date	Nov. 18, 2015
Cash Paid to Manager | $	$ 6,052
Dividend Nine [Member]
Dividends Payable [Line Items]
Declared	Feb. 18, 2016
Period Covered	Fourth quarter 2015
$ per Share | $ / shares	$ 1.15
Record Date	Mar. 3, 2016
Payable Date	Mar. 8, 2016
Cash Paid to Manager | $	$ 6,510
Dividend Ten [Member]
Dividends Payable [Line Items]
Declared	Apr. 28, 2016
Period Covered	First quarter 2016
$ per Share | $ / shares	$ 1.20
Record Date	May 12, 2016
Payable Date	May 17, 2016
Cash Paid to Manager | $	$ 6,981
Dividend Eleven [Member]
Dividends Payable [Line Items]
Declared	Jul. 28, 2016
Period Covered	Second quarter 2016
$ per Share | $ / shares	$ 1.25
Record Date	Aug. 11, 2016
Payable Date	Aug. 16, 2016
Cash Paid to Manager | $	$ 8,743
Dividend Twelve [Member]
Dividends Payable [Line Items]
Declared	Oct. 27, 2016
Period Covered	Third quarter 2016
$ per Share | $ / shares	$ 1.29
Record Date	Nov. 10, 2016
Payable Date	Nov. 15, 2016
Cash Paid to Manager | $	$ 5,620
Dividend Thirteen [Member]
Dividends Payable [Line Items]
Declared	Feb. 17, 2017
Period Covered	Fourth quarter 2016
$ per Share | $ / shares	$ 1.31
Record Date	Mar. 3, 2017
Payable Date	Mar. 8, 2017
Cash Paid to Manager | $		[1]
[1]	The amount of dividend payable to the Manager for the fourth quarter of 2016 will be determined on March 3, 2017, the record date.

Related Party Transactions (S78

Related Party Transactions (Schedule of Base Management Fees and Performance Fees) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended					3 Months Ended															12 Months Ended
	Jan. 31, 2017	Aug. 01, 2016	Jun. 30, 2016	Jul. 31, 2015	Oct. 31, 2014	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015		Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014		Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock Equity [Line Items]
Shares Issued						230,773
Performance fee reinvested					$ 51,600
Shares issued, for Performance fees to manager		944,046
Performance fee, settlement which was deferred		$ 67,800
Monthly volume weighted average share price			$ 71.84
Performance fee settled in cash				$ 67,800	$ 65,000
Subsequent Event [Member]
Common Stock Equity [Line Items]
Shares issued subsequent, for base management fees to manager	76,914
Macquarie Infrastructure Management (USA) Inc. [Member]
Common Stock Equity [Line Items]
Base management fees to be settled/settled in shares						$ 18,916		$ 18,382	$ 16,392	$ 14,796	$ 17,009	$ 18,118	$ 18,918		$ 16,545	$ 14,192	$ 13,915		$ 9,535	$ 8,994	$ 68,500	$ 70,600	$ 46,600
Performance fees to be settled/settled in shares and cash						$ 0		$ 0	$ 0	$ 0	$ 0	$ 0	$ 135,641		$ 148,728	$ 0	$ 116,586		$ 4,960	$ 0		$ 284,400	$ 121,500
Shares Issued						230,773	[1]	232,488	232,835	234,179	227,733	226,914	1,167,873	[2]	2,068,038	208,122	947,583	[3]	243,329	164,546
[1]	The Manager elected to reinvest all of the monthly base management fees for the fourth quarter of 2016 in shares. The Company issued 230,773 shares for the quarter ended December 31, 2016, including 76,914 shares that were issued in January 2017 for the December 2016 monthly base management fee.
[2]	In July 2015, the Board requested, and the Manager agreed, that $67.8 million of the performance fee for the quarter ended June 30, 2015 be settled in cash in July 2015 to minimize dilution. The remaining $67.8 million obligation was settled and reinvested in 944,046 shares by the Manager on August 1, 2016 using the June 2016 volume weighted average share price of $71.84.
[3]	In October 2014, the Board requested, and the Manager agreed, that $65.0 million of the performance fee for the quarter ended September 30, 2014 be settled in cash using the proceeds from the sale of the district energy business to minimize dilution. The remainder of the fee of $51.6 million was reinvested in additional shares of MIC.

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014		Jul. 16, 2014	Jul. 15, 2014
Components of Income Taxes [Line Items]
Net operating loss carry-forwards		$ 398,100
Net operating loss carry-forwards, subject to limitation		28,000
Deferred tax liability, noncurrent		896,116	$ 816,836	[1]
Total tax (benefit) provision	[2]	$ 71,257	(65,161)		$ (24,374)
Federal income tax rate		35.00%
Equity interest acquired							50.00%
Change in valuation allowance		$ 14,664	(2,358)		2,197
Earliest Tax [Member]
Components of Income Taxes [Line Items]
Net operating loss carry-forwards, expiration date		Jan. 1, 2028
Latest Tax [Member]
Components of Income Taxes [Line Items]
Net operating loss carry-forwards, expiration date		Dec. 31, 2035
2015 [Member]
Components of Income Taxes [Line Items]
Percentage of Bonus Depreciation		50.00%
2016 [Member]
Components of Income Taxes [Line Items]
Percentage of Bonus Depreciation		50.00%
2017 [Member]
Components of Income Taxes [Line Items]
Percentage of Bonus Depreciation		50.00%
2018 [Member]
Components of Income Taxes [Line Items]
Percentage of Bonus Depreciation		40.00%
2019 [Member]
Components of Income Taxes [Line Items]
Percentage of Bonus Depreciation		30.00%
IMTT [Member]
Components of Income Taxes [Line Items]
Percentage of ownership in IMTT								50.00%
Total tax (benefit) provision		$ (57,736)	$ (51,520)		$ (25,768)	[3]
The percentage for Dividend received deduction		80.00%
[1]	Conformed to current period presentation. See Note 2, “Summary of Significant Accounting Policies”, for Recently Issued Accounting Standards adopted during the year ended December 31, 2016.
[2]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.
[3]	Represents IMTT results subsequent to July 16, 2014, the date of the IMTT Acquisition.

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Income Taxes) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current taxes:
Federal		$ 0	$ (6,884)	$ 463
State		7,310	457	2,134
Total current tax provision (benefit)		7,310	(6,427)	2,597
Deferred taxes:
Federal		79,796	(46,744)	(23,339)
State		(1,185)	(14,348)	(1,435)
Total deferred tax provision (benefit)		78,611	(61,092)	(24,774)
Change in valuation allowance		(14,664)	2,358	(2,197)
Total tax provision (benefit)	[1]	$ 71,257	$ (65,161)	$ (24,374)
[1]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 186,948	$ 189,060
Deferred revenue	8,681	9,383
Accrued compensation	13,894	13,837
Accrued expenses	32,114	30,133
Unrealized losses on derivative instruments, net	0	6,482
Other	5,942	5,496
Total gross deferred tax assets	247,579	254,391
Less: valuation allowance	(4,319)	(18,983)
Net deferred tax assets	243,260	235,408
Deferred tax liabilities:
Intangible assets	(145,199)	(140,128)
Investment basis difference	(75,105)	(32,816)
Property and equipment	(892,382)	(877,065)
Unrealized gains on derivative instruments, net	(14,104)	0
Equity component convertible senior notes	(11,882)	0
Prepaid expenses	(704)	(2,235)
Total deferred tax liabilities	(1,139,376)	(1,052,244)
Net deferred tax liabilities	$ (896,116)	$ (816,836)

Income Taxes (Schedule of Recon

Income Taxes (Schedule of Reconciliation of Income Taxes) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Abstract]
Tax provision (benefit) at U.S. statutory rate		$ 79,144	$ (62,639)	$ 355,218
Permanent differences and other		(1,924)	1,299	3,418
State income taxes, net of federal benefit		8,958	(10,082)	(2,111)
Income attributable to noncontrolling interest		(257)	3,903	2,328
Gain from acquisition/divestiture of businesses		0	0	(347,772)
Tax effect of federal dividends received deduction		0	0	(8,029)
Basis adjustment for equity method investment		0	0	(25,229)
Change in valuation allowance		(14,664)	2,358	(2,197)
Total tax provision (benefit)	[1]	$ 71,257	$ (65,161)	$ (24,374)
[1]	Included $340,000 of benefit for income taxes from accumulated other comprehensive loss reclassifications for the year ended December 31, 2014.

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Operating leases rent expense	$ 53	$ 53	$ 38.5
Longest lease expiration period	January 2,063

Leases (Schedule of Future Mini

Leases (Schedule of Future Minimum Rental Commitments) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
2,017	$ 47,460
2,018	45,714
2,019	42,923
2,020	41,328
2,021	40,290
Thereafter	478,087
Total	$ 695,802

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Employer contributions - defined contribution plan			$ 2,500,000	$ 2,500,000	$ 2,100,000
IMTT [Member] | DB Plans Benefits [Member]
Defined Contribution Plan Disclosure [Line Items]
Final year compensation (as a percentage)			25.00%
Maximum compensation amount in final year			$ 25,000
Early retirement age			62 years
Consecutive period based on years of service and the employees' highest average compensation			5 years
IMTT [Member] | DB Plans Benefits [Member] | Bayonne Terminal Employees [Member]
Defined Contribution Plan Disclosure [Line Items]
Minimum required retirement age - defined benefit plan			65 years
IMTT [Member] | DB and Union Plans [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions - defined contribution plan	$ 20,000,000
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions - defined contribution plan			$ 3,500,000
Hawaii Gas Business [Member] | DB Plans Benefits [Member] | Scenario, Forecast [Member]
Defined Contribution Plan Disclosure [Line Items]
Employer contributions - defined contribution plan		$ 30,000
Hawaii Gas Business [Member] | PMLI Benefits [Member]
Defined Contribution Plan Disclosure [Line Items]
Minimum required retirement age - defined benefit plan			62 years
Minimum service period to eligible for participate			15 years
Maximum monthly premium after attaining age of 64 years			$ 150
Life insurance benefits for retirees - defined benefit plan			$ 1,000
Maximum age for which business pays medical premium of the retirees and spouses			64
Minimum [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage of employer's contribution under the defined contribution plan			0.00%
Maximum [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage of employer's contribution under the defined contribution plan			6.00%

Employee Benefit Plans (Additio

Employee Benefit Plans (Additional Information About Fair Value of Benefit Plan Assets Components of Net Periodic Cost and Projected Benefit Obligation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in benefit obligation:
Benefit obligation - beginning of year	$ 208,028	$ 217,400
Service cost	7,839	8,605	$ 3,924
Interest cost	9,192	8,814	4,998
Plan amendments	0	(110)
Participant contributions	53	126
Actuarial losses (gains)	11,826	(17,486)
Benefits paid	(9,567)	(9,321)
Liability (gain)/loss due to curtailment	(8,777)	0
Benefit obligation - end of year	218,594	208,028	217,400
Change in plan assets:
Fair value of plan assets - beginning of year	147,877	157,033
Actual return on plan assets	8,022	(772)
Employer contributions	4,641	811
Participant contributions	53	126
Benefits paid	(9,567)	(9,321)
Fair value of plan assets - end of year	151,026	147,877	157,033
Other Plan Benefits [Member]
Change in benefit obligation:
Benefit obligation - beginning of year	21,912	22,737
Service cost	810	911	409
Interest cost	974	912	480
Plan amendments	0	(110)
Participant contributions	53	126
Actuarial losses (gains)	4,476	(1,498)
Benefits paid	(1,417)	(1,166)
Liability (gain)/loss due to curtailment	0	0
Benefit obligation - end of year	26,808	21,912	22,737
Change in plan assets:
Fair value of plan assets - beginning of year	8,161	8,468
Actual return on plan assets	433	(78)
Employer contributions	1,141	811
Participant contributions	53	126
Benefits paid	(1,417)	(1,166)
Fair value of plan assets - end of year	8,371	8,161	8,468
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Change in benefit obligation:
Benefit obligation - beginning of year	50,044	52,266
Service cost	744	841	716
Interest cost	2,046	1,988	1,988
Plan amendments	0	0
Participant contributions	0	0
Actuarial losses (gains)	423	(2,752)
Benefits paid	(2,324)	(2,299)
Liability (gain)/loss due to curtailment	0	0
Benefit obligation - end of year	50,933	50,044	52,266
Change in plan assets:
Fair value of plan assets - beginning of year	42,825	45,475
Actual return on plan assets	2,716	(351)
Employer contributions	3,500	0
Participant contributions	0	0
Benefits paid	(2,324)	(2,299)
Fair value of plan assets - end of year	46,717	42,825	45,475
IMTT [Member] | DB Plans Benefits [Member]
Change in benefit obligation:
Benefit obligation - beginning of year	136,072	142,397
Service cost	6,285	6,853	2,799
Interest cost	6,172	5,914	2,530
Plan amendments	0	0
Participant contributions	0	0
Actuarial losses (gains)	6,927	(13,236)
Benefits paid	(5,826)	(5,856)
Liability (gain)/loss due to curtailment	(8,777)	0
Benefit obligation - end of year	140,853	136,072	142,397
Change in plan assets:
Fair value of plan assets - beginning of year	96,891	103,090
Actual return on plan assets	4,873	(343)
Employer contributions	0	0
Participant contributions	0	0
Benefits paid	(5,826)	(5,856)
Fair value of plan assets - end of year	$ 95,938	$ 96,891	$ 103,090

Employee Benefit Plans (Funded

Employee Benefit Plans (Funded Status) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Funded status
Funded status at end of year		$ (67,568)	$ (60,151)
Net amount recognized in balance sheet	[1]	(67,568)	(60,151)
Amounts recognized in balance sheet consisting of:
Noncurrent assets		0	222
Current liabilities		(1,160)	(916)
Noncurrent liabilities		(66,408)	(59,457)
Net amount recognized in balance sheet	[1]	$ (67,568)	(60,151)
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Period of average discount rate for defined benefit plans under statutory funding formulas		25 years
Statutory funding percentage		100.00%
Other Plan Benefits [Member]
Funded status
Funded status at end of year		$ (18,437)	(13,751)
Net amount recognized in balance sheet	[1]	(18,437)	(13,751)
Amounts recognized in balance sheet consisting of:
Noncurrent assets		0	222
Current liabilities		(1,160)	(916)
Noncurrent liabilities		(17,277)	(13,057)
Net amount recognized in balance sheet	[1]	(18,437)	(13,751)
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Funded status
Funded status at end of year		(4,216)	(7,219)
Net amount recognized in balance sheet	[1]	(4,216)	(7,219)
Amounts recognized in balance sheet consisting of:
Noncurrent assets		0	0
Current liabilities		0	0
Noncurrent liabilities		(4,216)	(7,219)
Net amount recognized in balance sheet	[1]	(4,216)	(7,219)
IMTT [Member] | DB Plans Benefits [Member]
Funded status
Funded status at end of year		(44,915)	(39,181)
Net amount recognized in balance sheet	[1]	(44,915)	(39,181)
Amounts recognized in balance sheet consisting of:
Noncurrent assets		0	0
Current liabilities		0	0
Noncurrent liabilities		(44,915)	(39,181)
Net amount recognized in balance sheet	[1]	$ (44,915)	$ (39,181)
[1]	Generally accepted accounting principles require measurement of defined benefit pension liabilities utilizing current discount rates. Statutory funding formulas permit measurement of defined benefit pension liabilities utilizing discount rates based on a 25-year average of those rates, which more closely matches the expected payout period for those liabilities. The IMTT and Hawaii Gas defined benefit pension plans both exceed 100% of the statutory funding target as of December 31, 2016.

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Not Yet Reflected in Net Periodic Benefit Cost and Included in Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Prior service credit		$ 95	$ 110
Accumulated loss		(27,171)	(23,764)
Accumulated other comprehensive loss		(27,076)	(23,654)
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		8,637	7,379	$ 4,406
Net amount recognized in balance sheet	[1]	(67,568)	(60,151)
All Other [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		(40,492)	(36,497)
Other Plan Benefits [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Prior service credit		95	110
Accumulated loss		(5,594)	(1,140)
Accumulated other comprehensive loss		(5,499)	(1,030)
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		1,358	1,202	911
Net amount recognized in balance sheet	[1]	(18,437)	(13,751)
Other Plan Benefits [Member] | All Other [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		(12,938)	(12,721)
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Prior service credit		0	0
Accumulated loss		(12,000)	(12,698)
Accumulated other comprehensive loss		(12,000)	(12,698)
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		1,196	1,042	558
Net amount recognized in balance sheet	[1]	(4,216)	(7,219)
Hawaii Gas Business [Member] | DB Plans Benefits [Member] | All Other [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		7,784	5,479
International Matex Tank Terminals [Member] | DB Plans Benefits [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Prior service credit		0	0
Accumulated loss		(9,577)	(9,926)
Accumulated other comprehensive loss		(9,577)	(9,926)
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		6,083	5,135	$ 2,937
Net amount recognized in balance sheet	[1]	(44,915)	(39,181)
International Matex Tank Terminals [Member] | DB Plans Benefits [Member] | All Other [Member]
Amounts not yet reflected in net periodic benefit cost and included in accumulated other comprehensive loss:
Net periodic benefit cost in excess (deficit) of cumulative employer contributions		$ (35,338)	$ (29,255)
[1]	Generally accepted accounting principles require measurement of defined benefit pension liabilities utilizing current discount rates. Statutory funding formulas permit measurement of defined benefit pension liabilities utilizing discount rates based on a 25-year average of those rates, which more closely matches the expected payout period for those liabilities. The IMTT and Hawaii Gas defined benefit pension plans both exceed 100% of the statutory funding target as of December 31, 2016.

Employee Benefit Plans (Compone

Employee Benefit Plans (Components of Net Periodic Benefit Cost and Other Changes in Other Comprehensive Income for Plans) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Components of net periodic benefit cost:
Service cost		$ 7,839		$ 8,605		$ 3,924
Interest cost		9,192		8,814		4,998
Expected return on plan assets		(9,324)		(10,275)		(5,500)
Recognized actuarial loss (gain)		945		318		901
Amortization of prior service (cost) credit		(15)		(83)		83
Net periodic benefit cost		8,637		7,379		4,406
Other changes recognized in other comprehensive (income) loss:
Prior service credit arising during the year		0		(110)		0
Net loss (gain) arising during the year		13,129		(6,441)		25,175
Liability gain due to curtailment		(8,777)		0		0
Amortization of prior service cost (credit)		15		83		(83)
Amortization of (loss) gain		(945)		(318)		(901)
Total recognized in other comprehensive (income) loss		3,422		(6,786)		24,191
Estimated amounts that will be amortized from accumulated other comprehensive loss over the next year:
Amortization of prior service cost (credit)		(15)		(15)
Amortization of net loss		1,058		930
Other Plan Benefits [Member]
Components of net periodic benefit cost:
Service cost		810		911		409
Interest cost		974		912		480
Expected return on plan assets		(502)		(585)		(183)
Recognized actuarial loss (gain)		91		(31)		200
Amortization of prior service (cost) credit		(15)		(5)		5
Net periodic benefit cost		1,358		1,202		911
Other changes recognized in other comprehensive (income) loss:
Prior service credit arising during the year		0		(110)		0
Net loss (gain) arising during the year		4,545		(836)		1,406
Liability gain due to curtailment		0		0		0
Amortization of prior service cost (credit)		15		5		(5)
Amortization of (loss) gain		(91)		31		(200)
Total recognized in other comprehensive (income) loss		4,469		(910)		$ 1,201
Estimated amounts that will be amortized from accumulated other comprehensive loss over the next year:
Amortization of prior service cost (credit)		(15)		(15)
Amortization of net loss		$ 264		$ 76
Weighted average assumptions to determine benefit obligations:
Rate of compensation increase	[1]	4.57%		4.57%		4.57%
Measurement date		--12-31		--12-31		--12-31
Weighted average assumptions to determine net cost:
Expected long-term rate of return on plan assets during fiscal year	[2]	6.25%		7.00%		7.00%
Rate of compensation increase	[1]	4.57%		4.57%		4.57%
Assumed healthcare cost trend rates:
Initial health care cost trend rate				7.50%
Other Plan Benefits [Member] | Maximum [Member]
Weighted average assumptions to determine benefit obligations:
Discount rate		4.25%		4.55%		4.15%
Weighted average assumptions to determine net cost:
Discount rate		4.55%		4.15%		4.45%
Assumed healthcare cost trend rates:
Initial health care cost trend rate		7.25%				7.80%
Ultimate rate		5.00%		5.00%		5.00%
Year ultimate rate is reached		2,028		2,028		2,028
Other Plan Benefits [Member] | Minimum [Member]
Weighted average assumptions to determine benefit obligations:
Discount rate		3.56%		3.78%		3.45%
Weighted average assumptions to determine net cost:
Discount rate		3.78%		3.45%		4.20%
Assumed healthcare cost trend rates:
Initial health care cost trend rate		7.20%				7.75%
Ultimate rate		4.50%		4.50%		4.50%
Year ultimate rate is reached		2,025		2,025		2,025
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Components of net periodic benefit cost:
Service cost		$ 744		$ 841		$ 716
Interest cost		2,046		1,988		1,988
Expected return on plan assets		(2,448)		(2,670)		(2,268)
Recognized actuarial loss (gain)		854		883		122
Amortization of prior service (cost) credit		0		0		0
Net periodic benefit cost		1,196		1,042		558
Other changes recognized in other comprehensive (income) loss:
Prior service credit arising during the year		0		0		0
Net loss (gain) arising during the year		156		268		7,925
Liability gain due to curtailment		0		0		0
Amortization of prior service cost (credit)		0		0		0
Amortization of (loss) gain		(854)		(883)		(122)
Total recognized in other comprehensive (income) loss		(698)		(615)		$ 7,803
Estimated amounts that will be amortized from accumulated other comprehensive loss over the next year:
Amortization of prior service cost (credit)		0		0
Amortization of net loss		$ 794		$ 854
Weighted average assumptions to determine benefit obligations:
Discount rate		4.00%		4.20%		3.90%
Measurement date		--12-31		--12-31		--12-31
Weighted average assumptions to determine net cost:
Discount rate		4.20%		3.90%		4.70%
Expected long-term rate of return on plan assets during fiscal year		5.90%		5.90%		5.90%
IMTT [Member] | DB Plans Benefits [Member]
Components of net periodic benefit cost:
Service cost		$ 6,285		$ 6,853		$ 2,799
Interest cost		6,172		5,914		2,530
Expected return on plan assets		(6,374)		(7,020)		(3,049)
Recognized actuarial loss (gain)		0		(534)		579
Amortization of prior service (cost) credit		0		(78)		78
Net periodic benefit cost		6,083		5,135		2,937
Other changes recognized in other comprehensive (income) loss:
Prior service credit arising during the year		0		0		0
Net loss (gain) arising during the year		8,428		(5,873)		15,844
Liability gain due to curtailment		(8,777)		0		0
Amortization of prior service cost (credit)		0		78		(78)
Amortization of (loss) gain		0		534		(579)
Total recognized in other comprehensive (income) loss		(349)		(5,261)		$ 15,187
Estimated amounts that will be amortized from accumulated other comprehensive loss over the next year:
Amortization of prior service cost (credit)		0		0
Amortization of net loss		$ 0		$ 0
Weighted average assumptions to determine benefit obligations:
Discount rate		4.30%		4.65%		4.25%
Rate of compensation increase		4.57%	[1]	4.57%	[1]	4.57%
Measurement date		--12-31		--12-31		--12-31
Weighted average assumptions to determine net cost:
Discount rate		4.65%		4.25%		4.55%
Expected long-term rate of return on plan assets during fiscal year		6.75%		7.00%		7.00%
Rate of compensation increase		4.57%	[1]	4.57%	[1]	4.57%
[1]	Only applies to IMTT post-retirement life insurance plan.
[2]	Only applies to IMTT Union Plan.

Employee Benefit Plans (DB Plan

Employee Benefit Plans (DB Plan Weighted Average Asset Allocation) (Details)	Dec. 31, 2016	Dec. 31, 2015
Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	100.00%	100.00%
Equity securities [Member] | Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	51.00%	58.00%
Fixed income securities [Member] | Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	48.00%	41.00%
Mixed income securities [Member] | Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	0.00%	0.00%
Private equity [Member] | Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	0.00%	0.00%
Cash [Member] | Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	1.00%	1.00%
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	100.00%	100.00%
Hawaii Gas Business [Member] | Equity securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	56.00%	60.00%
Hawaii Gas Business [Member] | Fixed income securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	27.00%	30.00%
Hawaii Gas Business [Member] | Mixed income securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	7.00%	8.00%
Hawaii Gas Business [Member] | Private equity [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	0.00%	0.00%
Hawaii Gas Business [Member] | Cash [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	10.00%	2.00%
IMTT [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	100.00%	100.00%
IMTT [Member] | Equity securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	51.00%	58.00%
IMTT [Member] | Fixed income securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	44.00%	37.00%
IMTT [Member] | Mixed income securities [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	0.00%	0.00%
IMTT [Member] | Private equity [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	4.00%	3.00%
IMTT [Member] | Cash [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
DB Plan Weighted Average Asset Allocations	1.00%	2.00%

Employee Benefit Plans (Asset A

Employee Benefit Plans (Asset Allocations) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	$ 151,026	$ 147,877	$ 157,033
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	147,598	145,197
Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	3,428	2,680
Cash and money market [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	5,890	3,138
Cash and money market [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	5,890	3,138
Cash and money market [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Cash and money market [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Equity securities - Domestic [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	63,552	66,290
Equity securities - Domestic [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	63,552	66,290
Equity securities - Domestic [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Equity securities - Domestic [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Equity securities - International [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	15,727	20,473
Equity securities - International [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	15,727	20,473
Equity securities - International [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Equity securities - International [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Fixed income securities - Domestic [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	59,028	50,860
Fixed income securities - Domestic [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	59,028	50,860
Fixed income securities - Domestic [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Fixed income securities - Domestic [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Fixed income securities - International [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets		1,035
Fixed income securities - International [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets		1,035
Fixed income securities - International [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets		0
Fixed income securities - International [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets		0
Domestic mixed income securities [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	3,401	3,401
Domestic mixed income securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	3,401	3,401
Domestic mixed income securities [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Domestic mixed income securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Domestic private equity [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	3,428	2,680
Domestic private equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Domestic private equity [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	0	0
Domestic private equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule Of Pension And Other Postretirement Benefits Expected Benefit Payments [Line Items]
Fair value of plan assets	$ 3,428	$ 2,680

Employee Benefit Plans (Estimat

Employee Benefit Plans (Estimated Future Benefit Payments) (Details) $ in Thousands	Dec. 31, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 11,552
2,018	10,108
2,019	11,080
2,020	12,619
2,021	11,946
Thereafter	66,207
Total	123,512
Other Plan Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	1,447
2,018	1,523
2,019	1,618
2,020	1,803
2,021	1,779
Thereafter	8,882
Total	17,052
Hawaii Gas Business [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	2,742
2,018	2,869
2,019	2,933
2,020	3,003
2,021	3,064
Thereafter	15,520
Total	30,131
IMTT [Member] | DB Plans Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	7,363
2,018	5,716
2,019	6,529
2,020	7,813
2,021	7,103
Thereafter	41,805
Total	$ 76,329

Legal Proceedings and Conting93

Legal Proceedings and Contingencies (Narrative) (Details) - IMTT [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Legal Proceedings and Contingencies [Line Items]
Minimum number of years for remediation activities	10 years
Maximum number of years for remediation activities	20 years
Minimum [Member]
Legal Proceedings and Contingencies [Line Items]
Estimated cost of remediation	$ 30
Maximum [Member]
Legal Proceedings and Contingencies [Line Items]
Estimated cost of remediation	$ 65

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - Subsequent Event [Member]	1 Months Ended
	Feb. 17, 2017$ / shares
Subsequent Event [Line Items]
Cash dividend declared, date declared	Feb. 17, 2017
Cash dividend declared per share	$ 1.31
Cash dividend declared, date to be paid	Mar. 8, 2017
Cash dividend declared, date of record	Mar. 3, 2017

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended																12 Months Ended
	Aug. 01, 2016	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue		$ 437,241		$ 420,524		$ 397,579		$ 396,387		$ 401,354		$ 415,709		$ 423,689		$ 398,498		$ 1,651,731	$ 1,639,250	$ 1,350,918
Operating income (loss)		80,200		75,658		76,507		88,776		59,985		73,449		(75,301)		(115,365)		321,141	(57,232)	36,855
Net income (loss) attributable to MIC		$ 72,808		$ 42,026		$ 19,192		$ 22,355		$ 32,923		$ 10,638		$ (63,096)		$ (89,002)		$ 156,381	$ (108,537)	$ 1,042,028
Per share information attributable to MIC :
Net income (loss) per share - basic		$ 0.89		$ 0.52		$ 0.24		$ 0.28		$ 0.41		$ 0.13		$ (0.80)		$ (1.22)		$ 1.93	$ (1.39)	$ 16.54
Net income (loss) per share - diluted		0.79	[1]	0.51	[1]	0.24	[1]	0.28	[1]	0.41	[1]	0.13	[1]	(0.80)	[1]	(1.22)	[1]	1.85	(1.39)	16.1
Cash dividends declared per share		$ 1.31		$ 1.29		$ 1.25		$ 1.20		$ 1.15		$ 1.13		$ 1.11		$ 1.07		$ 5.05	$ 4.46	$ 3.8875
Performance fee, settlement which is deferred	$ 67,800
Macquarie Infrastructure Management (USA) Inc. [Member] | deferred until July 2016 [Member]
Per share information attributable to MIC :
Performance fee, settlement which is deferred	$ 67,800
[1]	Diluted net income (loss) per share reflects the effect of potentially dilutive shares assuming: (i) the restricted stock unit grants provided to the independent directors had been fully converted to shares on the grant dates; (ii) the $67.8 million of the performance fee for the quarter ended June 30, 2015, which was reinvested in shares by the Manager on August 1, 2016, had been reinvested in shares by the Manager in July 2015; and (iii) the convertible senior notes that were issued in July 2014 and October 2016 had been fully converted into shares on the issue date. The potentially dilutive shares are excluded in the calculation if the effect is anti-dilutive or when the Company has a net loss for the period.