Atlas (ATCOL) 20-F 19 Mar 21 2020 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	ATLAS CORP.
Entity Central Index Key	0001794846
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	333-229312
Document Registration Statement	false
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Filer Category	Large Accelerated Filer
Document Accounting Standard	U.S. GAAP
ICFR Auditor Attestation Flag	true
Entity Preferred Stock, Shares Outstanding	33,335,570	33,335,570
Entity Incorporation, State or Country Code	1T
Entity Address, Address Line One	23 Berkeley Square
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	W1J 6HE
Entity Common Stock, Shares Outstanding	246,277,338
Business Contact [Member]
Document Information [Line Items]
Contact Personnel Name	Graham Talbot
Entity Address, Address Line One	23 Berkeley Square
Entity Address, City or Town	London
Entity Address, Country	GB
Entity Address, Postal Zip Code	W1J 6HE
City Area Code	+44
Local Phone Number	+44 20 7788 7819
Contact Personnel Fax Number	+ 44 843 320 5270
Series D Preferred Shares [Member]
Document Information [Line Items]
Entity Preferred Stock, Shares Outstanding	5,093,728
Title of 12(b) Security	Series D Preferred Shares, par value of $0.01 per share
Trading Symbol	ATCO-PD
Security Exchange Name	NYSE
Series E Preferred Shares [Member]
Document Information [Line Items]
Entity Preferred Stock, Shares Outstanding	5,415,937
Title of 12(b) Security	Series E Preferred Shares, par value of $0.01 per share
Trading Symbol	ATCO-PE
Security Exchange Name	NYSE
Series G Preferred Shares [Member]
Document Information [Line Items]
Entity Preferred Stock, Shares Outstanding	7,800,800
Title of 12(b) Security	Series G Preferred Shares, par value of $0.01 per share
Trading Symbol	ATCO-PG
Security Exchange Name	NYSE
Series H Preferred Shares [Member]
Document Information [Line Items]
Entity Preferred Stock, Shares Outstanding	9,025,105
Title of 12(b) Security	Series H Preferred Shares, par value of $0.01 per share
Trading Symbol	ATCO-PH
Security Exchange Name	NYSE
Series I Preferred Stock [Member]
Document Information [Line Items]
Entity Preferred Stock, Shares Outstanding	6,000,000
Title of 12(b) Security	Series I Preferred Shares, par value of $0.01 per share
Trading Symbol	ATCO-PI
Security Exchange Name	NYSE
Common Shares [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Shares, par value of $0.01 per share
Trading Symbol	ATCO
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 304,300,000	$ 195,000,000
Accounts receivable	75,900,000	18,700,000
Inventories	60,200,000	14,200,000
Prepaid expenses and other	33,900,000	17,600,000
Net investment in lease (note 7)	10,700,000	35,200,000
Acquisition related assets	99,300,000	0
Total current assets	584,300,000	280,700,000
Property, plant and equipment (note 8)	6,974,700,000	5,707,700,000
Right-of-use asset (note 9)	841,200,000	957,200,000
Net investment in lease (note 7)	418,600,000	723,600,000
Goodwill (note 10)	75,300,000	75,300,000
Deferred tax assets (note 16)	19,300,000	0
Other assets (note 11)	375,700,000	172,500,000
Total assets	9,289,100,000	7,917,000,000
Current liabilities:
Accounts payable and accrued liabilities (note 20(a))	134,100,000	83,400,000
Deferred revenue	28,200,000	20,300,000
Income tax payable (note 16)	110,400,000	0
Long-term debt - current (note 12)	332,100,000	363,700,000
Operating lease liabilities - current (note 13)	160,900,000	159,700,000
Other financing arrangements - current (note 14)	64,100,000	134,600,000
Other liabilities - current (note 15)	24,800,000	7,800,000
Total current liabilities	854,600,000	769,500,000
Long-term debt (note 12)	3,234,000,000	2,696,900,000
Operating lease liabilities (note 13)	669,300,000	782,600,000
Other financing arrangements (note 14)	801,700,000	373,900,000
Derivative instruments (note 22(c))	63,000,000	50,200,000
Other liabilities (note 15)	40,900,000	11,200,000
Total liabilities	5,663,500,000	4,684,300,000
Share capital (note 17):
Preferred shares; $0.01 par value; 150,000,000 shares authorized (2019 – 150,000,000); 33,335,570 shares issued and outstanding (2019 – 33,335,570)	0	0
Common shares, $0.01 par value; 400,000,000 shares authorized (2019 - 400,000,000); 246,031,989 shares issued and outstanding (2019 - 215,675,599), 727,351 shares held in treasury (2019 – 37,778)	2,400,000	2,100,000
Additional paid in capital	3,842,700,000	3,452,900,000
Deficit	(199,200,000)	(200,700,000)
Accumulated other comprehensive loss	(20,300,000)	(21,600,000)
Total shareholders' equity	3,625,600,000	3,232,700,000
Total liabilities and shareholders' equity	9,289,100,000	7,917,000,000
Commitments and contingencies (note 21)

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, authorized	150,000,000	150,000,000
Preferred shares, issued	33,335,570	33,335,570
Entity Preferred Stock, Shares Outstanding	33,335,570	33,335,570
Common shares, par value	$ 0.01	$ 0.01
Common shares, authorized	400,000,000	400,000,000
Common shares, issued	246,277,338	215,675,599
Common shares, outstanding	246,277,338	215,675,599
Treasury stock, shares	727,351	37,778

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue (note 5)	$ 1,421.1	$ 1,131.5	$ 1,096.3
Operating expenses (income):
Operating expenses	274.8	229.8	219.3
Depreciation and amortization	353.9	254.3	245.8
General and administrative	65.4	33.1	31.6
Operating leases (note 13)	150.5	154.3	129.7
Goodwill impairment (note 10)	117.9	0	0
Income related to modification of time charters	0	(227)	0
Total operating expenses	962.5	444.5	626.4
Operating earnings	458.6	687	469.9
Other expenses (income):
Interest expense	191.6	218.9	212.1
Interest income	(5)	(9.3)	(4.2)
Acquisition related gain on contract settlement	0	0	(2.4)
Loss (gain) on derivative instruments (note 22(c))	35.5	35.1	(15.5)
Equity income on investment	0	0	(1.2)
Other expenses	27.3	2	1.7
Total other expenses (income)	249.4	246.7	190.5
Net earnings before income tax	209.2	440.3	279.4
Income tax expense	16.6	1.2	0.6
Net earnings	$ 192.6	$ 439.1	$ 278.8
Earnings per share (note 18):
Class A common share, basic	$ 0.52	$ 1.72	$ 1.34
Class A common share, diluted	$ 0.50	$ 1.67	$ 1.31

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net earnings	$ 192.6	$ 439.1	$ 278.8
Other comprehensive income:
Amounts reclassified to net earnings during the year relating to cash flow hedging instruments (note 22(c))	1.3	1	1.1
Comprehensive income	$ 193.9	$ 440.1	$ 279.9

Consolidated Statements of Putt

Consolidated Statements of Puttable Preferred Shares and Shareholders' Equity - USD ($) $ in Millions	Total	Fairfax Financial Holdings Limited [Member]	Series D Puttable Preferred Shares [Member]	Class A Common Shares [Member]	Series I Preferred Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, AdjustmentSeries D Puttable Preferred Shares [Member]	Common Shares [Member]	Common Shares [Member]Fairfax Financial Holdings Limited [Member]	Common Shares [Member]Class A Common Shares [Member]	Common Shares [Member]Series I Preferred Stock [Member]	Common Shares [Member]Cumulative Effect, Period of Adoption, Adjustment	Non-puttable Preferred Shares [Member]	Non-puttable Preferred Shares [Member]Fairfax Financial Holdings Limited [Member]	Non-puttable Preferred Shares [Member]Class A Common Shares [Member]	Non-puttable Preferred Shares [Member]Series I Preferred Stock [Member]	Non-puttable Preferred Shares [Member]Cumulative Effect, Period of Adoption, Adjustment	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Fairfax Financial Holdings Limited [Member]	Additional Paid-in Capital [Member]Class A Common Shares [Member]	Additional Paid-in Capital [Member]Series I Preferred Stock [Member]	Additional Paid-in Capital [Member]Cumulative Effect, Period of Adoption, Adjustment	Deficit [Member]	Deficit [Member]Fairfax Financial Holdings Limited [Member]	Deficit [Member]Class A Common Shares [Member]	Deficit [Member]Series I Preferred Stock [Member]	Deficit [Member]Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member]Fairfax Financial Holdings Limited [Member]	Accumulated Other Comprehensive Loss [Member]Class A Common Shares [Member]	Accumulated Other Comprehensive Loss [Member]Series I Preferred Stock [Member]	Accumulated Other Comprehensive Loss [Member]Cumulative Effect, Period of Adoption, Adjustment
Balance at Dec. 31, 2017	$ 1,949.4							$ 0.9					$ 0.3					$ 2,753					$ (781.1)					$ (23.7)
Puttable preferred shares Balance, Shares at Dec. 31, 2017			0
Puttable preferred shares, Balance at Dec. 31, 2017			$ 0
Balance, shares at Dec. 31, 2017	32,872,706							131,664,101
Net earnings	$ 278.8							$ 0					0					0					278.8					0
Other comprehensive income	1.1							0					0					0					0					1.1
Shares issued, value				$ 13.9	$ 150					$ 0	$ 0				$ 0	$ 0.1				$ 13.9	$ 149.9				$ 0	$ 0				$ 0	$ 0
Shares issued, shares					6,000,000					2,514,996
Preferred shares issued			$ 46.7
Preferred shares issued, shares			1,986,449
Warrants issued	67.5							$ 0					0					67.5					0					0
Warrants issued, shares								0
Exercise of warrants	328.7							$ 0.5					0					328.2					0					0
Exercise of warrants, shares								38,461,539
Fees and expenses in connection with issuance of common and preferred shares	(74.3)							$ 0					0					(74.3)					0					0
Dividends on Class A common shares	(72.7)							0					0					0					(72.7)					0
Dividends on preferred shares	(68.7)							0					0					0					(68.7)					0
Puttable preferred shares accretion of preferred shares with holder put option			$ 1.4
Accretion of preferred shares with holder put option	(1.5)							0					0					0					(1.5)					0
Redemption of Series F preferred shares	$ (140)							0					(0.1)					(139.9)					0					0
Redemption of Series F preferred shares, shares	(5,600,000)
Shares issued through dividend reinvestment program	$ 22.8							$ 0					0					22.8					0					0
Shares issued through dividend reinvestment program, shares								2,986,159
Share-based compensation expense	3.1							$ 0					0					3.1					0					0
Share-based compensation expense, shares								325,221
Other share-based compensation	1.9							$ 0					0					2.3					(0.4)					0
Other share-based compensation, shares								890,927
Treasury shares, value	0							$ 0					0					0					0					0
Treasury shares								(7,106)
Puttable preferred shares, Balance at Dec. 31, 2018			$ 48.1				$ 0
Puttable preferred shares Balance, Shares at Dec. 31, 2018			1,986,449				0
Balance at Dec. 31, 2018	$ 2,460					$ 181.1		$ 1.4				$ 0	$ 0.3				$ 0	3,126.5				$ 0	(645.6)				$ 181.1	(22.6)				$ 0
Balance, shares at Dec. 31, 2018	33,272,706							176,835,837					33,272,706
Adjusted balance at Dec. 31, 2018	$ 2,641.1							$ 1.4					$ 0.3					3,126.5					(464.5)					(22.6)
Puttable preferred shares Adjusted balance, shares at Dec. 31, 2018			1,986,449
Adjusted balance at Dec. 31, 2018			$ 48.1
Adjusted balance, shares at Dec. 31, 2018								176,835,837					33,272,706
Net earnings	439.1							$ 0					$ 0					0					439.1					0
Other comprehensive income	1							0					0					0					0					1
Exercise of puttable preferred shares	0							0					0					0					0					0
Exercise of puttable preferred shares, shares			(1,923,585)
Exercise of puttable preferred shares			$ (47.7)
Cancellation of put option on puttable preferred shares	1.6							0					$ 0					1.6					0					0
Cancellation of put option on puttable preferred shares, shares			(62,864)
Cancellation of put option on puttable preferred shares			$ (1.6)
Cancellation of put option on puttable preferred shares, shares													62,864
Exercise of warrants	321.6							$ 0.4					$ 0					321.2					0					0
Exercise of warrants, shares								38,461,539
Fees and expenses in connection with issuance of common and preferred shares		$ (0.2)							$ 0					$ 0					$ (0.2)					$ 0					$ 0
Dividends on Class A common shares	(103)							$ 0					0					0					(103)					0
Dividends on preferred shares	(70.4)							0					0					0					(70.4)					0
Puttable preferred shares accretion of preferred shares with holder put option			1.2
Accretion of preferred shares with holder put option	(1.2)							0					0					0					(1.2)					0
Shares issued through dividend reinvestment program	1.2							$ 0					0					1.2					0					0
Shares issued through dividend reinvestment program, shares								122,148
Share-based compensation expense	1.9							$ 0					0					2.6					(0.7)					0
Share-based compensation expense, shares								257,799
Treasury shares, value	0							$ 0					0					0					0					0
Treasury shares								(1,724)
Puttable preferred shares, Balance at Dec. 31, 2019			$ 0
Puttable preferred shares Balance, Shares at Dec. 31, 2019			0
Balance at Dec. 31, 2019	3,232.7					$ (2.3)		$ 1.8				$ 0	$ 0.3				$ 0	3,452.9				$ 0	(200.7)				$ (2.3)	(21.6)				$ 0
Balance, shares at Dec. 31, 2019								215,675,599					33,335,570
Adjusted balance at Dec. 31, 2019	3,230.4							$ 1.8					$ 0.3					3,452.9					(203)					(21.6)
Adjusted balance, shares at Dec. 31, 2019								215,675,599					33,335,570
Net earnings	192.6							$ 0					$ 0					0					192.6					0
Other comprehensive income	1.3							0					0					0					0					1.3
Common shares issued on acquisition	316.8							$ 0.2					0					316.6					0					0
Common shares issued on acquisition, shares								29,891,266
Common shares issued on loan settlement	8.3							$ 0.1					0					8.2					0					0
Common shares issued on loan settlement, shares								775,139
Dividends on Class A common shares	(120.7)							$ 0					0					0					(120.7)					0
Dividends on preferred shares	(67.1)							0					0					0					(67.1)					0
Shares issued through dividend reinvestment program	0							$ 0					0					0.3					(0.3)					0
Shares issued through dividend reinvestment program, shares								30,007
Share-based compensation expense	6.4							$ 0					0					7.1					(0.7)					0
Share-based compensation expense, shares								1,398,553
Treasury shares, value	0							$ 0					0					0					0					0
Treasury shares								37,778
Unissued acquisition related equity consideration	80.8							$ 0					0					80.8					0					0
Cancellation of unissued acquisition related equity consideration	(1.3)							0					0					(1.3)					0					0
Issuance of common shares from unissued acquisition related equity consideration	0							$ 0					0					0					0					0
Issuance of common shares from unissued acquisition related equity consideration, shares								318,637
Return of common shares to unissued acquisition related equity consideration	0							$ 0					0					0					0					0
Return of common shares to unissued acquisition related equity consideration, shares								(727,351)
Cancellation of common shares issued on acquisition	(12.5)							$ 0					0					(12.5)					0					0
Cancellation of common shares issued on acquisition, shares								(1,122,290)
Equity component on issuance of Exchangeable Notes, net of issuance costs	6.1							$ 0					0					6.1					0					0
Premium paid on capped call	(15.5)							0					0					(15.5)					0					0
Balance at Dec. 31, 2020	$ 3,625.6							$ 2.1					$ 0.3					$ 3,842.7					$ (199.2)					$ (20.3)
Balance, shares at Dec. 31, 2020								246,277,338					33,335,570

Consolidated Statements of Pu_2

Consolidated Statements of Puttable Preferred Shares and Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class A Common Shares [Member]
Dividends per common share	$ 0.50	$ 0.50	$ 0.50
Series D Preferred Shares [Member]
Dividends per preferred share	1.99	1.99	1.99
Series E Preferred Shares [Member]
Dividends per preferred share	2.06	2.06	2.06
Series F Preferred Shares [Member]
Dividends per preferred share			1.77
Series G Preferred Shares [Member]
Dividends per preferred share	2.05	2.05	2.05
Series H Preferred Shares [Member]
Dividends per preferred share	1.97	1.97	1.97
Series I Preferred Stock [Member]
Dividends per preferred share	$ 2	$ 2	$ 0.23

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net earnings	$ 192,600,000	$ 439,100,000	$ 278,800,000
Items not involving cash:
Depreciation and amortization	353,900,000	254,300,000	245,800,000
Impairment	117,900,000	0	0
Change in right-of-use asset	120,140,000	111,810,000	0
Non-cash interest expense and accretion	40,500,000	38,400,000	20,200,000
Deferred gain on sale-leasebacks	0	0	(23,600,000)
Unrealized change in derivative instruments	12,900,000	(20,000,000)	(57,400,000)
Amortization of acquired revenue contracts	16,900,000	13,800,000	8,100,000
Other	6,100,000	1,500,000	(500,000)
Change in other operating assets and liabilities (note 20(b))	(166,700,000)	(55,900,000)	53,700,000
Cash from operating activities	694,200,000	783,000,000	525,100,000
Investing activities:
Expenditures for property, plant and equipment	(783,500,000)	(332,500,000)	(319,200,000)
Short-term investments	0	2,500,000	(2,400,000)
Prepayment on vessel purchase	(82,200,000)	(13,000,000)	0
Payment on settlement of interest swap agreements	(21,800,000)	(126,800,000)	(41,300,000)
Cash and restricted cash acquired from APR Energy acquisition	50,600,000	0	0
Acquisition of GCI	0	0	(333,600,000)
Cash acquired from GCI acquisition	0	0	70,100,000
Loss on cash repatriation	(18,700,000)	0	0
Receipt from contingent consideration asset	11,100,000	0	0
Other assets	(15,400,000)	(5,800,000)	(1,000,000)
Cash used in investing activities	(859,900,000)	(475,600,000)	(627,400,000)
Financing activities:
Repayments of long-term debt and other financing arrangements	(1,122,200,000)	(1,961,900,000)	(535,300,000)
Issuance of long-term debt and other financing arrangements	1,383,500,000	1,227,300,000	372,600,000
Issuance of Exchangeable Notes	201,300,000	0	0
Purchase of capped call	(15,500,000)	0	0
Preferred shares issued, net of issuance costs	0	0	144,400,000
Notes and warrants issued	100,000,000	250,000,000	250,000,000
Proceeds from exercise of warrants	0	250,000,000	250,000,000
Redemption of preferred shares	0	(47,700,000)	(143,400,000)
Financing fees	(49,100,000)	(27,000,000)	(16,100,000)
Dividends on common shares	(120,000,000)	(101,800,000)	(49,900,000)
Dividends on preferred shares	(67,100,000)	(70,400,000)	(65,800,000)
Cash from (used in) financing activities	310,900,000	(481,500,000)	206,500,000
Increase (decrease) in cash and cash equivalents	145,200,000	(174,100,000)	104,200,000
Cash and cash equivalents and restricted cash, beginning of year	197,300,000	371,400,000	267,200,000
Cash and cash equivalents and restricted cash, end of year	$ 342,500,000	$ 197,300,000	$ 371,400,000

General

General	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
General	1. General: Atlas Corp. (the “Company” or “Atlas”) owns, leases and operates a fleet of containerships and power generation assets through its containership leasing and mobile power generation segments, respectively. It is a Republic of the Marshall Islands corporation incorporated on October 1, 2019 for the purpose of facilitating the Reorganization (as defined below). On November 20, 2019, Seaspan Corporation (“Seaspan”) entered into an Agreement and Plan of Merger with the Company, then a wholly owned subsidiary of Seaspan, and Seaspan Holdco V Ltd., a wholly owned subsidiary of Atlas, in order to implement a reorganization of Seaspan’s corporate structure into a holding company structure, pursuant to which Seaspan would become a direct, wholly owned subsidiary of Atlas (the “Reorganization”). On February 27, 2020, the Reorganization was completed. Common and preferred shareholders of Seaspan (the predecessor publicly held parent company) became common and preferred shareholders of Atlas, as applicable, on a one-for-one basis, maintaining the same number of shares and ownership percentage held in Seaspan immediately prior to the Reorganization. Atlas assumed all of Seaspan’s share purchase warrants and equity plans and will perform all relevant obligations. Atlas common shares trade on the New York Stock Exchange under the ticker symbol “ATCO”. On February 28, 2020, after the Reorganization, Atlas completed the acquisition of all the issued and outstanding common shares of Apple Bidco Limited, which owns 100% of APR Energy Limited (collectively “APR Energy”) (see note 3). The outbreak of COVID-19, which was declared a pandemic by the World Health Organization, has had a negative effect on the global economy and has adversely impacted the industries that Atlas operates in. In the containership industry, there were significant improvements in charter rates and reductions in idle capacity in the latter half of the year, signaling recovery. In the power generation industry, while COVID-19 continues to impact developing countries, which reduces general power demand in some areas, it has not materially impacted the Company's ability to execute contracts in the peaking power and emergency power segments of the market in which the it operates. However, the situation continues to evolve and the impact of the pandemic on both industries remain unpredictable. As a result, this increases the uncertainties and the degree of judgment associated with many of the Company’s estimates and assumptions. As events develop and additional information becomes available, the Company’s estimates may change in future periods.

Significant accounting policies

Significant accounting policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Significant accounting policies	2. Significant accounting policies: (a) Basis of preparation: The Reorganization was accounted for as a transaction among entities under common control under the pooling of interest method and represented a change in reporting entity whereby the financial information of Seaspan prior to the Reorganization was assumed by Atlas on a carry-over basis. Accordingly, the accompanying consolidated financial statements represent the consolidated historical operations and changes in consolidated financial position of Seaspan, which included the Company as a consolidated subsidiary from its incorporation on October 1, 2019 to February 27, 2020 and those of the Company thereafter, following the Reorganization. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America and the following accounting policies have been consistently applied in the preparation of the consolidated financial statements. (b) Principles of consolidation: The accompanying consolidated financial statements include the accounts of Atlas Corp. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated upon consolidation. The Company also consolidates any variable interest entities (“VIEs”) of which it is the primary beneficiary. The primary beneficiary is the enterprise that has both the power to make decisions that most significantly affect the economic performance of the VIE and has the right to receive benefits or the obligation to absorb losses that in either case could potentially be significant to the VIE. The impact of the consolidation of these VIEs is described in note 14. The Company accounts for its investment in companies in which it has significant influence by the equity method. The Company’s proportionate share of earnings is included in earnings and added to or deducted from the cost of the investment. (c) Foreign currency translation: The functional and reporting currency of the Company is the United States dollar. Transactions involving other currencies are converted into United States dollars using the exchange rates in effect at the time of the transactions. At the balance sheet date, monetary assets and liabilities that are denominated in currencies other than the United States dollar are translated into United States dollars using exchange rates at that date. Exchange gains and losses are included in net earnings. (d) Cash equivalents: Cash equivalents include highly liquid securities with terms to maturity of three months or less when acquired. (e) Inventories: Inventories consist primarily of spare parts and consumables. Inventories are stated at the lower of cost or net realizable value. Inventory cost is primarily determined using average or weighted average cost method, depending on the nature of the inventory. Net realizable value is the estimated selling price in the ordinary course of business less costs to complete, disposal and transportation. 2. Significant accounting policies (continued): (f) Property, plant and equipment: Vessels Except as described below, vessels are recorded at their cost, which consists of the purchase price, acquisition and delivery costs, less accumulated depreciation. Vessels purchased from Seaspan’s predecessor upon completion of Seaspan’s initial public offering in 2005 were initially recorded at the predecessor’s carrying value. Depreciation is calculated on a straight-line basis over the estimated useful life of each vessel, which is 30 years from the date of completion. The Company calculates depreciation based on the estimated remaining useful life and the expected salvage value of the vessel. Power generating equipment Power generating equipment are recorded at their costs, which represent its original cost at the time of purchase, less accumulated depreciation. Costs incurred to mobilize and install power-generating equipment pursuant to a contract for the provision of power generation services are recorded in property, plant and equipment and are depreciated on a straight-line basis over the non-cancellable lease term to which the power generating equipment relates. A summary of the useful lives used for calculating depreciation and amortization is as follows: Turbines 25 years Generators 15 years Transformers 15 years Property, plant and equipment that are held for use are evaluated for impairment when events or circumstances indicate that their carrying amounts may not be recoverable from future undiscounted cash flows. Such evaluations include the comparison of current and anticipated operating cash flows, assessment of future operations and other relevant factors. If the carrying amount of the property, plant and equipment exceeds the estimated net undiscounted future cash flows expected to be generated over the asset’s remaining useful life, the carrying amount of the asset is reduced to its estimated fair value. (g) Vessel dry-dock activities: Classification society rules require that vessels be dry-docked for inspection including planned major maintenance and overhaul activities for ongoing certification. The Company generally dry-docks its vessels once every five years. Dry-docking activities include the inspection, refurbishment and replacement of steel, engine components, electrical, pipes and valves, and other parts of the vessel. The Company uses the deferral method of accounting for dry-dock activities whereby capital costs incurred are deferred and amortized on a straight-line basis over the period until the next scheduled dry-dock activity. (h) Business combinations: Business combinations are accounted for under the acquisition method. The acquired identifiable net assets are measured at fair value at the date of acquisition. Deferred taxes are recognized for any differences between the fair value of net assets acquired and the related tax basis. Any excess of the purchase price over the fair value of net assets acquired is recognized as goodwill. Associated transaction costs are expensed as incurred. 2. Significant accounting policies (continued): (i) Goodwill: Goodwill represents the excess of the purchase price of an acquired enterprise over the fair value assigned to assets acquired and liabilities assumed in a business combination. Goodwill is not amortized, but reviewed for impairment annually or more frequently if impairment indicators arise. When goodwill is reviewed for impairment, the Company may elect to assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. Alternatively, the Company may bypass this step and use a fair value approach to identify potential goodwill impairment and, when necessary, measure the amount of impairment. The Company uses a discounted cash flow model to determine the fair value of reporting units, unless there is a readily determinable fair market value. (j) Asset retirement obligations: The Company records a provision and a corresponding long-lived asset for asset retirement obligations (“ARO”) when there is a legal obligation associated with the retirement of long-lived assets and the fair value of the liability can be reasonably estimated. The fair value of the ARO is measured using expected future cash flows discounted at the Company’s credit-adjusted risk-free interest rate. The liability is accreted up to the cost of retirement through interest expense over the non-cancellable lease term. The long-lived asset is depreciated straight-line over the same period. Changes in the amount or timing of the estimated ARO are recorded as an adjustment to the related asset and liability. (k) Deferred financing fees: Deferred financing fees represent the unamortized costs incurred on issuance of the Company’s credit facilities and other financing arrangements and are presented as a direct deduction from the related debt liability when available. Amortization of deferred financing fees on credit facilities is provided on the effective interest rate method over the term of the facility based on amounts available under the facilities. Amortization of deferred financing fees on other financing arrangements is provided on the effective interest rate method over the term of the underlying obligation. Amortization of deferred financing fees is recorded as interest expense. ( l ) Revenue: Containership leasing revenue The Company derives revenue from the charter of its containership vessels. Each charter agreement is evaluated and classified as an operating lease or financing lease based on the lease term, fair value associated with the lease and any purchase options or obligations. The assessment is done at lease commencement and reassessed only when a modification occurs that is not considered a separate contract. Charters classified as operating leases include a lease component associated with the use of the vessel and a non-lease component related to vessel management. Total consideration in the lease agreement is allocated between the lease and non-lease components based on their relative standalone selling prices. For arrangements where the timing and pattern of transfer to the lessee is consistent between the lease and non-lease components and the lease component, if accounted for separately, would be classified as an operating lease, the Company has elected to treat the lease and non-lease components as a single lease component. Revenue is recognized each day the vessels are on-hire, managed and performance obligations are satisfied. 2. Significant accounting policies (continued): (l) Revenue (continued): Containership leasing revenue (continued): For charters that are classified as direct financing leases and sales-type leases, the present value of minimum lease payments and any unguaranteed residual value are recognized as net investment in lease. The discount rate used in determining the present values is the interest rate implicit in the lease. The lower of the fair value of the vessel based on information available at lease commencement date and the present value of the minimum lease payments computed using the interest rate implicit specific to each lease, represents the price, from which the carrying value of the vessel and any initial direct costs are deducted in order to determine the selling profit or loss. For financing leases that are classified as direct financing leases, the unearned lease interest income including any selling profit and initial direct costs are deferred and amortized to income over the period of the lease so as to produce a constant periodic rate of return on the net investment in lease. Any selling loss is recognized at lease commencement date. For financing leases that are classified as sales-type leases, any selling profit or loss is recognized at lease commencement date. Initial direct costs are expensed at lease commencement date if the fair value of the vessel is different from its carrying amount. If the fair value of the vessel is equal to its carrying amount, initial direct costs should be deferred and amortized to income over the term of the lease. Power generation revenue The Company also derives revenue from lease and service contracts that provide customers with comprehensive power generation services that include leasing of the power generation equipment, installation and dismantling services, operations and maintenance of the power generating equipment (“O&M”), operations monitoring and logistical support. The Company earns a fixed portion of revenue on these contracts by providing megawatt capacity to its customers. Each power equipment lease contract may, depending on its terms, contain a lease component, a non-lease component or both. Lease classification is determined on a contract-specific basis. Total consideration in contracts that include a lease component associated with the use of the power-generation equipment and a non-lease component related to O&M is allocated between the lease and non-lease components based on their relative standalone selling prices. For arrangements where the timing and pattern of transfer to the lessee is consistent between the lease and non-lease components and the lease component, if accounted for separately, would be classified as an operating lease, the Company has elected to treat the components as a single lease component. Revenue is recognized over the period in which the equipment is available to the customer for use and service is provided to the customer. Certain contracts provide for mobilization and decommissioning payments. Mobilization revenue received up front is deferred and recognized as revenue on a straight-line basis over the term of the contract. Decommissioning revenue is recognized ratably over the term of the contract, as it is earned. (m) Leases: Leases classified as operating leases, where the Company is the lessee, are recorded as lease liabilities based on the present value of minimum lease payments over the lease term, discounted using the lessor’s rate implicit in the lease for each individual lease arrangement or the Company’s incremental borrowing rate, if the lessor’s implicit rate is not readily determinable. The lease term includes all periods covered by renewal and termination options where the Company is reasonably certain to exercise the renewal options or not to exercise the termination options. Corresponding right-of-use assets are recognized consisting of the lease liabilities, initial direct costs and any lease incentive payments. 2. Significant accounting policies (continued) (m) Leases (continued): Lease liabilities are drawn down as lease payments are made and right-of-use assets are depreciated over the term of the lease. Operating lease expenses are recognized on a straight-line basis over the term of the lease, consisting of interest accrued on the lease liability and depreciation of the right-of-use asset, adjusted for changes in index-based variable lease payments in the period of change. Lease payments on short-term operating leases with lease terms of twelve months or less are expensed as incurred. Transactions are accounted for as sale-leaseback transactions when control of the asset is transferred. For sale-leaseback transactions, where the Company is the seller-lessee, any gains or losses on sale are recognized upon transfer. (n) Derivative financial instruments: From time to time, the Company utilizes derivative financial instruments. All of the Company’s derivatives are measured at their fair value at the end of each period. Derivatives that mature within one year are classified as current. For derivatives not designated as accounting hedges, changes in their fair value are recorded in earnings. The Company’s hedging policies permit the use of various derivative financial instruments to manage interest rate risk. The Company had previously designated certain of its interest rate swaps as accounting hedges and applied hedge accounting to those instruments. By September 30, 2008, the Company de-designated all of the interest rate swaps it had accounted for as hedges to that date. Subsequent to their de-designation dates, changes in their fair value are recorded in earnings. The Company evaluates whether the occurrence of any of the previously hedged interest payments are considered to be remote. When the previously hedged interest payments are not considered remote of occurring, unrealized gains or losses in accumulated other comprehensive income associated with the previously designated interest rate swaps are recognized in earnings when and where the interest payments are recognized. If such interest payments are identified as being remote, the accumulated other comprehensive income balance pertaining to these amounts is reversed through earnings immediately. (o) Income taxes: The Company accounts for income taxes using the asset and liability method. Under the liability method, deferred tax assets and liabilities are recognized for the anticipated future tax effects of temporary differences between the accounting basis and the tax basis of the Company’s assets and liabilities using the applicable jurisdictional tax rates. A valuation allowance for deferred tax assets is recorded when it is more likely than not that some or all of the benefit from the deferred tax asset will not be realized. The Company recognizes the tax benefits of uncertain tax positions only if it is more-likely-than-not that a tax position taken or expected to be taken in a tax return will be sustained upon examination by the taxing authorities, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense in the Company's consolidated statements of operations. 2. Significant accounting policies (continued) (p) Share-based compensation: The Company grants phantom share units, restricted shares, restricted stock units and stock options to certain of its officers, members of management and directors as compensation. Compensation cost is measured at the grant date fair values as follows: • Restricted shares, phantom share units and restricted stock units are measured based on the quoted market price of the Company’s common shares on the date of the grant. • Stock options are measured at fair value using the Black-Scholes model. The fair value of each grant is recognized on a straight-line basis over the requisite service period. The Company accounts for forfeitures in share-based compensation expense as they occur. (q) Fair value measurement: Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e. the “exit price”) in an orderly transaction between market participants at the measurement date. The hierarchy is broken down into three levels based on the observability of inputs as follows: • Level 1 — Valuations based on quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. Valuation adjustments and block discounts are not applied to Level 1 instruments. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not entail a significant degree of judgment. • Level 2 — Valuations based on one or more quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement. (r) Earnings per share: The treasury stock method is used to compute the dilutive effect of the Company’s share-based compensation awards, warrants and convertible instruments, where the presumption of share settlement has been overcome. Under this method, the incremental number of shares used in computing diluted earnings per share (“EPS”) is the difference between the number of shares assumed issued and purchased using assumed proceeds. The if-converted method is used to compute the dilutive effect of the Company’s convertible instruments where the presumption of share settlement has not been overcome. Under the if-converted method, the instruments are assumed to have been converted at the share price applicable at the end of the period, if dilutive. Contingently issuable shares are included in diluted EPS as of the beginning of the period, if contingencies are satisfied by the end of the period. If contingencies have not been satisfied by the end of the period, the number of contingently issuable shares included in diluted EPS is based on the number of shares, if any, that would be issuable if the end of the reporting period were the end of the contingency period, if the result is dilutive. The cumulative dividends applicable to the Series D, E, G, H and I preferred shares reduce the earnings available to common shareholders, even if not declared. (s) Use of estimates: The preparation of consolidated financial statements requires management to make estimates and assumptions that affect the: 2. Significant accounting policies (continued): (s) Use of estimates (continued): • reported amounts of assets and liabilities, • disclosure of contingent assets and liabilities at the balance sheet dates; and • reported amounts of revenue and expenses during the reporting fiscal periods. Areas where accounting judgments and estimates are significant to the Company and where actual results could differ from those estimates, include, but are not limited to the: • assessment of going concern; • assessment of property, plant and equipment useful lives; • expected salvage values; • recoverability of the carrying value of property, plant and equipment and intangible assets with finite lives which are subject to future market events; • carrying value of goodwill; • fair values of assets acquired and liabilities assumed from business combination; • fair value of asset retirement obligations; and • fair value of interest rate swaps, other derivative financial instruments and contingent consideration asset. (t) Comparative information: Certain information has been reclassified to conform to the financial statement presentation adopted for the current year. (u) Recently adopted accounting pronouncement: Leases Effective January 1, 2019, the Company adopted ASU 2016-02, “Leases”, using the modified retrospective method, whereby a cumulative effect adjustment was made as of the date of initial application. The Company elected the practical expedient to use the effective date of adoption as the date of initial application. Accordingly, financial information and disclosures in the comparative period were not restated. It also elected to apply the package of practical expedients such that for any expired or existing leases, it did not reassess lease classification, initial direct costs or whether the relevant contracts are or contain leases. The Company did not use hindsight to reassess lease term for the determination of impairment of right-of-use assets. The impacts of the adoption of ASU 2016-02 are as follows: (in millions of US dollars) As reported at December 31, 2018 Adjustments Adjusted at January 1, 2019 Right-of-use assets (1) (2) $ — $ 1,068.3 $ 1,068.3 Other assets (2) 204.9 (17.3 ) 187.6 Accounts payable and accrued liabilities (1) 70.2 (2.5 ) 67.7 Current portion of operating lease liabilities (1) — 160.2 160.2 Current portion of other long-term liabilities (3) 32.2 (22.2 ) 10.0 Operating lease liabilities (1) — 893.3 893.3 Other long-term liabilities (3) 181.1 (158.9 ) 22.2 Deficit (3) (645.6 ) 181.1 (464.5 ) ___________________ (1) Upon adoption of ASU 2016-02, the Company recorded non-cash right-of-use assets and operating lease liabilities on the balance sheet for its vessel sale-leaseback transactions and office leases under operating lease arrangements. Prior to January 1, 2019, operating leases were not included on the balance sheet and were recorded as operating lease expenses when incurred. The amount recognized as operating lease liabilities was based on the present value of future minimum lease payments, discounted using the lessor’s rate implicit in the lease or the Company’s incremental borrowing rate if the lessor’s implicit rate is not readily determinable and includes any existing accrued payments related to lease liabilities. Minimum lease payments referenced to an indexed rate were determined based on the respective rates at the adoption date. (2) Initial direct costs related to the Company’s vessel sale-leaseback transactions under operating lease arrangements were reclassified from other assets to right-of-use assets. (3) Deferred gain related to the Company’s vessel sale-leaseback transactions was recognized through deficit on the initial date of application. The accounting for lessors is largely unchanged under ASU 2016-02. The Company evaluated its lessor arrangements and determined that the amounts recognized and the pattern of recognition remained substantially the same as existing guidance which was previously used. Leases are classified as operating leases or financing leases based on the lease term and fair value associated with the lease. The assessment is done at lease commencement and reassessed only when a modification occurs that is not considered a separate contract. Measurement of credit loss Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) 2016-13, “Measurement of Credit Loss on Financial Instruments”. ASU 2016-13 replaces the current incurred loss impairment methodology with the expected credit loss impairment model (“CECL”), which requires consideration of a broader range of reasonable and supportable information to estimate expected credit losses over the life of the instrument instead of only when losses are incurred. This standard applies to financial assets measured at amortized cost basis and net investments in leases recognized by the lessor. Upon adoption, a cumulative effect adjustment of $2,293,000 was made to deficit as part of the modified retrospective transition approach. Simplifying test for goodwill impairment Effective January 1, 2020, the Company adopted ASU 2017-04, “Simplifying the Test for Goodwill Impairment.” ASU 2017-04 eliminates the need to determine the fair value of individual assets and liabilities of a reporting unit to measure the implied goodwill impairment. As a result of the adoption, the Company now calculates goodwill impairment as the amount by which the carrying value exceeds fair value of a reporting unit, not to exceed the carrying amount of goodwill. (v) Discontinuation of LIBOR In March 2020, FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848)”, which provides optional relief for the discontinuation of LIBOR resulting from rate reform. Contract terms that are modified due to the replacement of a reference rate are not required to be remeasured or reassessed under FASB’s relevant U.S. GAAP Topic. The election is available by Topic. This guidance is effective for all entities as of March 12, 2020 through December 31, 2022 and may be applied from the beginning of an interim period that includes the issuance date of the ASU. The Company is currently evaluating the impact this guidance. 2. Significant accounting policies (continued): (w) Recent accounting pronouncements Debt with conversion and other options In August 2020, FASB issued ASU 2020-06, “Debt – Debt with Conversion and Other Options (Subtopic 470-20)”, which simplifies the accounting for convertible debt instruments by reducing the number of accounting models and circumstances when embedded conversion features are separately recognized. This update also revises the method in which diluted EPS is calculated related to certain instruments with conversion features, among other clarifications. The guidance is effective for annual reporting periods beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company is currently evaluating the impact of this guidance.

Acquisition of Apple Bidco Limi

Acquisition of Apple Bidco Limited	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisition of Apple Bidco Limited	3. Acquisition of Apple Bidco Limited On February 28, 2020, the Company acquired 100.0% of the share capital of APR Energy from Fairfax Financial Holdings Ltd. and its affiliates (“Fairfax”) and certain other minority shareholders (collectively, the “Sellers”). Fairfax held 67.8% of APR Energy’s common shares. APR Energy owns and operates a fleet of capital-intensive assets, including gas turbines and other power generation equipment, and provides power solutions to customers through various contracts. The financial results of APR Energy have been included in the Company’s consolidated financial statements from February 29, 2020, after the date of acquisition, and include revenue of $198,300,000 and net earnings of $4,000,000 from that date through December 31, 2020. At closing, Atlas issued 29,891,266 common shares and reserved 6,664,270 common shares for future issuance (the “Holdback Shares”). The Holdback Shares are issuable over a period of 90 days to five years after the date of acquisition and are subject to settlement of purchase price adjustments, indemnification arrangements and other future compensable events. These arrangements may be settled, at the Sellers’ option, by either cancellation of Holdback Shares or cash. In the case of purchase price adjustments, and certain inventory mechanisms, if Holdback Shares are insufficient, Sellers may choose to compensate the Company in cash or cancel previously issued common shares. Any Holdback Shares that are not cancelled after the expiry of their respective holdback periods, will be issued to the Sellers, plus any accrued distributions or dividends. The net purchase price of $287,700,000 comprises of the following. Adjustments have been made from what was originally reported as a result of settlement of purchase price adjustments: As originally reported Adjustments As adjusted 29,891,266 common shares issued (1) $ 316.8 — $ 316.8 6,664,270 Holdback Shares (1) 70.6 — 70.6 Less: Contingent consideration asset (2) (41.5 ) (53.7 ) (95.2 ) Less: Purchase price adjustment (3) (52.5 ) 48.0 (4.5 ) Net purchase price $ 293.4 $ (5.7 ) $ 287.7 (1) (2) (3) 3. Acquisition of Apple Bidco Limited (continued): The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date. Adjustments have been made from what was previously reported as a result of settlement of purchase price adjustments and refinements of estimates. As originally reported Adjustments As adjusted Cash and cash equivalents $ 36.7 — $ 36.7 Inventory 54.4 (13.5 ) 40.9 Acquisition related assets (1) 65.0 31.4 96.4 Accounts receivable (2) 41.4 7.7 49.1 Other current assets 7.9 1.2 9.1 Property, plant and equipment 597.3 (150.1 ) 447.2 Intangible assets 35.4 (8.0 ) 27.4 Deferred tax assets 23.5 (6.9 ) 16.6 Other assets 13.9 — 13.9 Goodwill — 117.9 117.9 Total assets acquired 875.5 (20.3 ) 855.2 Accounts payable and accrued liabilities 91.3 1.2 92.5 Income tax payable 104.0 2.5 106.5 Other current liabilities 17.2 — 17.2 Long-term debt (including current and non-current portions) (3) 311.6 — 311.6 Deferred tax liabilities 7.0 (6.0 ) 1.0 Other long-term liabilities 51.0 (12.3 ) 38.7 Net assets acquired $ 293.4 $ (5.7 ) $ 287.7 (1) (2) (3) The carrying amounts of cash and cash equivalents, accounts receivable and other current assets (consisting of prepaid expenses), accounts payable and accrued liabilities, income taxes payable and other current liabilities approximate their fair values due to the short-term maturity of the instruments. The fair value of long-term debt and other assets are categorized within Level 2 of the fair value hierarchy and determined based on expected payments. The fair values of contingent consideration assets, inventory, property, plant and equipment, intangible assets and asset retirement obligation included in other long-term liabilities were categorized within Level 3 of the fair value hierarchy and were determined using relevant market assumptions, including comparable sales and cost data, discount rates and future cash flows. As part of the acquisition, the Company recorded $117,900,000 of goodwill r esulting from expected synergies in congruence with APR’s unique position in the power generation market, which is not deductible for tax purposes and has been assigned to the power generation segment. During the year ended December 31, 2020, the Company recognized $1,498,000 of acquisition related costs that were included in general and administrative expense. Cost recognized in the fourth quarter of 2019 was $2,294,000. 3. Acquisition of Apple Bidco Limited (continued): Pro forma financial information The following table presents unaudited pro forma results for the year ended December 31, 2020 and 2019. The unaudited pro forma financial information combines the results of operations of the Company and APR Energy as though the acquisition had occurred as of January 1, 2019. The pro forma results contain adjustments that are directly attributable to the transaction, including depreciation of the fair value of property, plant and equipment, amortization of acquired intangible assets, and refinancing of debt. Additionally, pro forma net earnings were adjusted to exclude acquisition-related costs incurred. Year ended December 31, Pro forma information 2020 2019 Revenue $ 1,464.6 $ 1,452.9 Net earnings 179.3 454.4

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Reporting	4. Segment reporting: For management purposes, the Company is organized based on its two leasing businesses and has two reportable segments, containership leasing and mobile power generation. The Company’s containership leasing segment owns and operates a fleet of containerships which are chartered primarily pursuant to long-term, fixed-rate charters. The Company’s mobile power generation segment owns and operates a fleet of power generation assets, including gas turbines and other equipment, and provides power solutions to customers. The Company’s chief operating decision makers monitor the operating results of the leasing businesses separately for the purpose of making decisions about resource allocation and performance assessment. In the second quarter of 2020, The financial results of APR Energy have been included in the Company’s consolidated financial statements from February 29, 2020, after the date of acquisition. The following table includes the Company’s selected financial information by segment: Year ended December 31, 2020 Containership Leasing Mobile Power Generation Elimination and Other Total Revenue $ 1,222.8 $ 198.3 $ — $ 1,421.1 Operating expense 243.4 31.4 — 274.8 Depreciation and amortization expense 288.1 65.8 — 353.9 General and administrative expense 36.6 36.9 (8.1 ) 65.4 Operating leases 147.3 3.2 — 150.5 Goodwill impairment — 117.9 — 117.9 Interest expense 176.0 19.5 (3.9 ) 191.6 Interest income (1.4 ) (3.6 ) — (5.0 ) Income tax expense 1.0 15.6 — 16.6 4 . Segment reporting (continued): Year ended December 31, 2020 Containership leasing adjusted EBITDA $ 795.5 Mobile power generation adjusted EBITDA 127.0 Total segment adjusted EBITDA 922.5 Eliminations and other (1.3 ) Depreciation and amortization 353.9 Interest expense 191.6 Interest income (5.0 ) Loss on derivative instruments 35.5 Other expenses 8.6 Gain on contingent consideration asset (6.8 ) Loss on foreign currency repatriation 18.7 Loss on sale 0.2 Goodwill impairment 117.9 Consolidated net earnings before taxes $ 209.2 December 31, 2020 Containership Leasing Mobile Power Generation Elimination and Other Total Total assets $ 8,475.4 $ 829.9 $ (16.2 ) $ 9,289.1 Capital expenditures by segment: Year ended December 31, 2020 Containership leasing $ 848.1 Mobile power generation 17.6

Revenue

Revenue	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue	5. Revenue: The Company generates revenue by leasing and operating its fleet of containerships and power generation assets, largely through operating leases, direct financing leases and sales-type leases. Revenue disaggregated by segment and by type for the year ended December 31, 2020 is as follows: Containership Leasing (1) Mobile Power Generation Total Operating lease revenue $ 1,180.0 $ 187.4 $ 1,367.4 Interest income from leasing 40.5 — 40.5 Other 2.3 10.9 13.2 $ 1,222.8 $ 198.3 $ 1,421.1 (1) 5 . Revenue (continued) : Prior to the acquisition of APR Energy on February 28, 2020, for the year ended December 31, 2019 and 2018, our results were fully attributable to containership leasing. Revenue disaggregated by type for the year ended December 31, 2019 and 2018 are as follows: 2019 2018 Operating lease revenue $ 1,096.0 $ 1,061.1 Interest income from leasing 35.5 35.2 $ 1,131.5 $ 1,096.3 As at December 31, 2020, the minimum future revenues to be received on committed operating leases, interest income to be earned from direct financing leases and other revenue are as follows: Operating lease revenue (1) Direct financing leases (2) Other Total committed revenue 2021 $ 1,354.1 $ 36.1 $ 10.0 $ 1,400.2 2022 1,051.1 34.4 4.1 1,089.6 2023 722.9 32.5 0.7 756.1 2024 447.9 30.3 — 478.2 2025 264.6 28.2 — 292.8 Thereafter 274.6 180.7 — 455.3 $ 4,115.2 $ 342.2 $ 14.8 $ 4,472.2 (1) (2) As at December 31, 2020, the minimum future revenues to be received based on each segment are as follows: Containership Leasing (1) (2) Mobile Power Generation Total committed revenue 2021 $ 1,243.1 $ 157.1 $ 1,400.2 2022 1,000.9 88.7 1,089.6 2023 718.0 38.1 756.1 2024 478.2 — 478.2 2025 292.8 — 292.8 Thereafter 455.3 — 455.3 $ 4,188.3 $ 283.9 $ 4,472.2 (1) (2) Minimum future revenues assume 100% utilization, extensions only at the Company’s unilateral option and no renewals. In March 2019, the Company entered into an agreement with a customer to modify seven time charters such that the charters terminated effective March 31, 2019, subsequent to which the vessels were re-chartered to other customers. Pursuant to this agreement, the Company received a settlement payment of $227,000,000, which was recorded in income related to modification of time charters. 5. Revenue (continued): The Company’s revenue is derived from the following customers: 2020 2019 2018 COSCO $ 401.1 $ 407.4 $ 412.3 Yang Ming Marine 255.7 257.5 235.6 ONE 237.3 199.4 241.6 Other 527.0 267.2 206.8 $ 1,421.1 $ 1,131.5 $ 1,096.3

Related party transactions

Related party transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related party transactions	6. Related party transactions: Prior to March 13, 2018, the Company had a 10.8% equity interest in GCI. The Company purchased the remaining 89.2% interest in GCI on March 13, 2018 and consolidated GCI from the date of acquisition. The income or expenses with related parties relate to amounts paid to or received from individuals or entities that are associated with the Company or with the Company’s directors or officers and these transactions are governed by pre-arranged contracts. On each of February 14, 2018 and January 15, 2019, the Company issued to Fairfax $250,000,000 aggregate principal of 5.50% senior notes, due on February 14, 2025 (“2025 Notes”) and January 15, 2026 (“2026 Notes”), respectively, and a tranche of warrants to purchase 38,461,539 common shares of Seaspan at an exercise price of $6.50 per share, on each date. On May 31, 2018, the Company entered into an agreement with Fairfax whereby Fairfax agreed to (i) exercise the warrants issued in February 2018 on July 16, 2018 and (ii) exercise the 2019 warrants upon issuance thereof on January 15, 2019. In exchange, Seaspan issued to Fairfax warrants to purchase 25,000,000 common shares of Seaspan at an exercise price of $8.05 per share. These warrants remain outstanding and are exercisable for common shares of the Company. On February 28, 2020, Seaspan issued to Fairfax, in a private placement, $100,000,000 aggregate principal amount of 5.50% senior notes due on March 1, 2027 (the “2027 Fairfax Notes” and together with the 2025 Notes and the 2026 Notes, the “Fairfax Notes”) (note 12(e) ). On February 28, 2020, in connection with the acquisition of APR Energy, Fairfax received 23,418,798 common shares of Atlas as consideration for its equity interests in APR Energy and as settlement of indebtedness owing to Fairfax by APR Energy . In connection with purchase price adjustments, Fairfax forfeited its right to receive 391,246 Holdback Shares and returned 1,253,883 previously issued common shares to Atlas. Of the 1,253,883 common shares returned, 760,807 shares were permanently forfeited; 493,076 shares are held in reserve as treasury shares and may be issuable to Fairfax at a future date, subject to settlement of potential indemnified events . During the year ended December 31, 2020, 318,637 common shares were issued to Fairfax out of Holdback Shares. At December 31, 2020, Fairfax held approximately % of the Company’s issued and outstanding common shares and has designated two members to the Company’s board of directors. For the year ended December 31, 2020, interest expense related to the 2025 Notes, the 2026 Notes and the 2027 Fairfax Notes, excluding amortization of the debt discount, was $ 32,114,000 ( 2019 – $26,927,000, 2018 – $19,380,000). For the year ended December 31, 2020, amortization of debt discount was $19,963,000 (2019 – $17,347,000, 2018 – $7,310,000).

Net investment in lease

Net investment in lease	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Net investment in lease	7 . Net investment in lease: 2020 2019 Undiscounted lease receivable $ 773.2 $ 1,224.2 Unearned interest income (343.9 ) (465.4 ) Net investment in lease $ 429.3 $ 758.8 2020 2019 Lease receivables $ 429.3 $ 608.8 Unguaranteed residual value - 150.0 Net investment in lease 429.3 758.8 Current portion of net investment in lease (10.7 ) (35.2 ) Long-term portion of net investment in lease $ 418.6 $ 723.6 Between August 2017 and January 2018, the Company received delivery of five 11000 TEU vessels that immediately commenced fixed-rate bareboat charters with a 17-year term. At the end of their respective lease terms, the customer has agreed to purchase the vessels for $32,000,000 each. Each transaction is considered a direct financing lease and accounted for as a disposition of vessels upon delivery of each vessel. In November 2019, the Company entered into an agreement to acquire six vessels and their existing fixed-rate bareboat charters. Five vessels were delivered in December 2019 and one vessel was delivered in January 2020. The acquired bareboat charter agreements included the option for the charterer to purchase each vessel for an amount equal to fair market value, subject to minimum and maximum purchase prices. At the date of acquisition, it was determined that the customer was reasonably certain to exercise these purchase options. Accordingly, these leases were classified as sales-type leases and accounted for as a disposition of vessels upon their respective delivery dates. In February 2020, the bareboat charters for the six vessels acquired in November 2019 were modified to extend the terms of the leases by six years, with similar purchase options. As a result of the modification, it was determined that the customer is no longer reasonably certain to exercise the purchase options and these leases were reclassified as operating leases. At December 31, 2020, the minimum lease receivable from direct financing leases are as follows: 2021 $ 44.3 2022 44.3 2023 44.3 2024 44.5 2025 44.4 Thereafter 551.4 $ 773.2

Property, plant and equipment

Property, plant and equipment	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Property, plant and equipment	8. Property, plant and equipment: Accumulated Net book December 31, 2020 Cost depreciation value Vessels $ 9,148.9 $ (2,571.3 ) $ 6,577.6 Equipment and other 543.1 (146.0 ) 397.1 Property, plant and equipment $ 9,692.0 $ (2,717.3 ) $ 6,974.7 Accumulated Net book December 31, 2019 Cost depreciation value Vessels $ 8,018.5 $ (2,311.4 ) $ 5,707.1 Equipment and other 4.6 (4.0 ) 0.6 Property, plant and equipment $ 8,023.1 $ (2,315.4 ) $ 5,707.7 8. Property, plant and equipment (continued): During the year ended December 31, 2020, depreciation and amortization expense relating to property, plant and equipment was $324,597,000 (2019 - $233,729,000, 2018 – $219,330,000). In February 2020, the Company acquired gas turbines and other equipment of $447,166,000 as part of the acquisition of APR Energy (note 3). In February 2020, sales-type leases related to six bareboat charters were re-assessed to be operating leases at lease modification. Accordingly, vessels of $377,393,000 During the year ended December 31, 2020 the Company took delivery of ten secondhand vessels, with an aggregate purchase price of $785,033,000, including one vessel that was reclassified to property, plant and equipment from net investment in leases at lease modification, subsequent to initial acquisition during the year.

Right-of-use assets

Right-of-use assets	12 Months Ended
	Dec. 31, 2020
Operating Lease Right Of Use Assets [Abstract]
Right-of-use assets	9. Right-of-use assets: December 31, 2020 Cost Accumulated amortization Net book value Vessel operating leases $ 1,060.9 $ (228.0 ) $ 832.9 Other operating leases 13.6 (5.3 ) 8.3 Right-of-use assets $ 1,074.5 $ (233.3 ) $ 841.2 December 31, 2019 Cost Accumulated amortization Net book value Vessel operating leases $ 1,060.9 $ (110.1 ) $ 950.8 Office operating leases 8.2 (1.8 ) 6.4 Right-of-use assets $ 1,069.1 $ (111.9 ) $ 957.2 During the year ended December 31, 2020, change in right-of-use assets was $120,140,000 (2019 - $111,810,000).

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	10. Goodwill: Containership leasing Mobile power generation Balance, December 31, 2019 $ 75.3 $ — Goodwill arising from acquisition of APR Energy (note 3) — 117.9 Impairment loss recognized during the period — (117.9 ) Balance, December 31, 2020 $ 75.3 $ — Upon the acquisition of APR Energy, the Company recognized $117,900,000 of goodwill. As part of the Company’s annual goodwill impairment test, it was determined that the carrying value of the mobile power generation reporting unit exceeded its fair value, as a result of potential strategic repositioning contemplated subsequent to acquisition. Fair value was determined using a discounted cash flow approach. As a result, an impairment loss of $117,900,000 equal to the balance of goodwill related to the mobile power generation reporting unit, was recognized.

Other assets

Other assets	12 Months Ended
	Dec. 31, 2020
Other Assets [Abstract]
Other assets	11. Other assets: 2020 2019 Intangible assets (a) $ 104.8 $ 94.0 Deferred dry-dock (b) 63.8 41.3 Restricted cash (c) 38.2 — Contingent consideration asset (d) 84.0 — Vessels under construction (e) 42.0 — Other 42.9 37.2 Other assets $ 375.7 $ 172.5 (a) Intangible assets: December 31, 2020 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (58.6 ) $ 71.3 Trademark 27.4 (1.1 ) 26.3 Other 11.5 (4.3 ) 7.2 $ 168.8 $ (64.0 ) $ 104.8 December 31, 2019 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (39.3 ) $ 90.6 Other 6.6 (3.2 ) 3.4 $ 136.5 $ (42.5 ) $ 94.0 As part of the acquisition of APR Energy on February 28, 2020, the Company recorded $27,400,000 related to the fair value of a trademark. The trademark is amortized on a straight-line basis over its estimated useful life of 20 years. Acquired customer contracts are amortized on a straight-line basis over their remaining useful lives. As of December 31, 2020, the weighted average remaining useful lives of acquired customer contracts was 5 years (2019 – 5 years). During the year ended December 31, 2020, the Company recorded $21,396,000 of amortization related to intangible assets (2019 – $20,729,000, 2018 – $16,569,000). Future amortization of intangible assets is as follows: 2021 $ 19.1 2022 18.2 2023 14.5 2024 11.7 2025 8.3 Thereafter 33.0 $ 104.8 11 . Other assets (continued): (b) Deferred dry-dock: During the year ended December 31, 2020, changes in deferred dry-dock were as follows: December 31, 2018 36.7 Costs incurred 23.5 Amortization expensed (1) (18.9 ) December 31, 2019 41.3 Costs incurred 45.2 Amortization expensed (1) (22.7 ) December 31, 2020 $ 63.8 (1) Amortization of dry-docking costs is included in depreciation and amortization (c) Restricted cash: Restricted cash consists primarily of amounts held in reserve accounts related to the Company’s debt facilities. (d) Contingent consideration asset: As a part of the acquisition of APR Energy on February 28, 2020, the Company is compensated by the Sellers for certain losses that may be incurred on future cash repatriation from a foreign jurisdiction until the earlier of (1) reaching the maximum cash flows subject to compensation, (2) termination of specified contracts, (3) sustaining the ability to repatriate cash without losses and (4) April 30, 2022. The amount of compensation depends on the Company’s ability to generate cash flows on specific contracts in the foreign jurisdiction and the magnitude of losses incurred on repatriation. The maximum amount of cash flows subject to compensation is $110,000,000. Fairfax agreed, subject to definitive documentation, to compensate the Company for future losses realized on sale or disposal of certain property, plant and equipment and inventory items calculated as the difference between the proceeds on sale or disposal and the book value of the respective assets at February 28, 2020, prior to acquisition. The maximum amount of losses subject to compensation is $64,000,000. Contingent consideration asset, December 31, 2019 $ — Assets acquired 95.2 Change in fair value 6.8 Compensation received (11.1 ) Contingent consideration asset 90.9 Current portion included in prepaid expenses and other (6.9 ) Contingent consideration asset, December 31, 2020 $ 84.0 (e) Vessels under construction: Vessels under construction include installment payments, interest and financing costs incurred on the construction of new vessels, net of address commissions. In November 2020, the Company entered into agreements with a shipyard to build five 12200 TEU vessels for an aggregate purchase price of $419,825,000, net of address commissions, payable in four installments (note 21(b)). As of December 31, 2020, $41,982,500, net of address commissions, relating to the first installment was paid.

Long-term debt

Long-term debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-term debt	12. Long term debt: 2020 2019 Long-term debt: Revolving credit facilities (a) (c) $ 772.1 $ 867.0 Term loan credit facilities (b) (c) 2,094.7 1,799.4 Senior unsecured notes (d) 80.0 80.0 Fairfax Notes (e) 600.0 500.0 Exchangeable Notes (f) 201.3 — 3,748.1 3,246.4 Fair value adjustment on term loan credit facilities (0.1 ) (0.1 ) Debt discount on Fairfax Notes ( e ) (130.9 ) (150.9 ) Debt discount on Exchangeable Notes (f) (6.1 ) — Deferred financing fees (44.9 ) (34.8 ) Long-term debt 3,566.1 3,060.6 Current portion of long-term debt (332.1 ) (363.7 ) Long-term debt $ 3,234.0 $ 2,696.9 (a) Revolving credit facilities As at December 31, 2020, the Company had five revolving credit facilities available (December 31, 2019 – four revolving credit facilities) which provided for aggregate borrowings of up to $989,119,000 (December 31, 2019 – $987,012,000), of which $217,000,000 On February 28, 2020, the Company acquired the outstanding debt of APR Energy. Concurrently, the Company entered into a credit facility of up to $185,000,000 (the “Bank Facility”) comprised of a revolving loan facility of $50,000,000 and a term loan facility of $135,000,000, the proceeds of which were used to refinance the APR Energy’s outstanding debt. The Bank Facility matures on February 28, 2023 and is secured by the Company’s power generation assets. On July 2, 2020, the Company entered into a $150,000,000 revolving credit facility, refinancing a $150,000,000 revolving credit facility due to mature in August 2020. The new facility matures on July 2, 2022 and can increase to a maximum capacity of $200,000,000, subject to additional commitments. The revolving credit facilities drawn mature between December 31, 2022 and May 15, 2024. The following is a schedule of future minimum repayments under the Company’s revolving facilities as of December 31, 2020: 2021 $ 50.7 2022 392.2 2023 82.2 2024 247.0 2025 - Thereafter - $ 772.1 12. Long term debt (continued): (a) Revolving credit facilities (continued): As at December 31, 2020, the one month, three month and six month average LIBOR on the Company’s revolving credit facilities was 0.2%, 0.2% and 0.3%, respectively (December 31, 2019 – one month and three months average LIBOR of 1.8% and 1.9%, respectively) and the margins ranged between 0.5% and 2.25% (December 31, 2019 – 0.5% and 2.25%). The weighted average rate of interest, including the margin, for the Company’s revolving credit facilities was 1.4% as at December 31, 2020 (December 31, 2019 – 2.9%). Interest payments are made monthly, quarterly and semi-annually. The Company is subject to commitment fees ranging between 0.2% and 0.6% (December 31, 2019 – 0.2% and 0.5%) calculated on the undrawn amounts under the various facilities. For one of the revolving credit facilities, semi-annual payments commence thirty-six months after delivery of the associated newbuild containership for the facility. One revolving credit facility, with a principal outstanding of $58,240,000, is due in full at maturity on December 31, 2023. Another revolving credit facility with a principal outstanding of $283,000,000, will be converted into a term loan facility on May 15, 2022. (b) Term loan credit facilities As at December 31, 2020, the Company had $2,344,730,000 (December 31, 2019 - $1,954,375,000) of term loan credit facilities available, of which $250,000,000 (December 31, 2019 - $155,000,000) was undrawn. Three of the term loan credit facilities have a revolving loan component, all of which have been included in the revolving facilities above. On February 28, 2020, the Company entered into the Bank Facility which includes a $135,000,000 term loan facility (note 12(a)). On March 6, 2020, the Company entered into a $100,000,000 term loan credit facility, which bears a fixed interest rate of 7.7% per annum and matures on March 6, 2026. This facility is secured by the Company’s power generation assets. In February 2020 and March 2020, the Company increased the aggregate commitment under an existing term loan credit facility (the “December 2019 Term Loan”), which matures on December 30, 2025, by $100,000,000. On October 15, 2020, the Company entered into a sustainability-linked term loan facility (the “October 2020 Term Loan”) with an aggregate principal of $200,000,000, which was subsequently upsized to $250,000,000 on December 14, 2020. The facility matures on October 14, 2026 and bears an initial interest rate of 2.25% margin plus three month LIBOR. The margin may be subsequently adjusted if the Company meets certain sustainability metrics during the term of the loan. No amounts have been drawn under the facility as of December 31, 2020. The December 2019 Term Loan and the October 2020 Term Loan are secured by a portfolio of vessels, which also secured some of the Company’s other credit facilities. 1 2 . Long term debt (continued): (b) Term loan credit facilities (continued): Term loan credit facilities mature between December 23, 2021 and January 21, 2030. The following is a schedule of future minimum repayments under the Company’s term loan credit facilities as of December 31, 2020: 2021 $ 286.1 2022 187.9 2023 364.5 2024 877.2 2025 222.7 Thereafter 156.3 $ 2,094.7 For all of the Company’s term loan credit facilities, except for one, interest is calculated based on three month or six month LIBOR plus a margin per annum, dependent on the interest period selected by the Company. The three month and six month average LIBOR was 0.2% and 0.3%, respectively (December 31, 2019 – 2.0% and 2.1%) and the margins ranged between 0.4% and 4.3% as at December 31, 2020 (December 31, 2019 – 0.4% and 4.3%). For one of our term loan credit facilities with a total principal amount outstanding of $39,970,000 (December 31, 2019 - $52,743,000), interest is calculated based on the Export-Import Bank of Korea (KEXIM) rate plus 0.7% The weighted average rate of interest, including the applicable margin, was 2.7% as at December 31, 2020 (December 31, 2019 – 4.0%) for the Company’s term loan credit facilities. One of the Company’s term loan credit facilities bears interest at a fixed rate of 7.7% Repayments under term loan credit facilities are made in quarterly or semi-annual payments. For those related to newbuilding containerships, payments commence three, six or thirty-six months after delivery of the associated newbuilding containership, utilization date or the inception date of the term loan credit facilities. (c) Credit facilities – other: As at December 31, 2020, the Company’s credit facilities were secured by first-priority mortgages granted on most of its power generation assets and 70 of its vessels together with other related security. The security for each of the Company’s current secured credit facilities includes: • A first priority mortgage on collateral assets; • An assignment of the Company’s lease agreements and earnings related to the related collateral assets; • An assignment of the insurance policies covering each of the collateral assets that are subject to a related mortgage and/or security interest; • An assignment of the Company’s related shipbuilding contracts and the corresponding refund guarantees; • A pledge over shares of various subsidiaries; and • A pledge over the related retention accounts. 12. Long term debt (continued): (c) Credit facilities – other (continued): As at December 31, 2020, $1,582,470,000 principal amount of indebtedness under the Company’s term loan and revolving credit facilities was secured by a portfolio of 48 vessels, the composition of which can be changed, and is subject to a borrowing base and portfolio concentration requirements, as well as compliance with financial covenants and certain negative covenants. The Company may prepay certain amounts outstanding without penalty, other than breakage costs in certain circumstances. A prepayment may be required as a result of certain events, including without limitation the sale or loss of a vessel, a termination or expiration of a charter (and the inability to enter into a replacement charter acceptable to lenders within a prescribed period of time). The amount that must be prepaid may be calculated based on the loan to market value of the Company’s assets. In these circumstances, valuations of the Company’s assets are conducted on a “without lease” and/or a “orderly liquidation” basis as required under the credit facility agreement. Each credit facility contains a mix of financial covenants requiring the Company to maintain minimum liquidity, tangible net worth, interest and principal coverage ratios, and debt-to-assets ratios, as defined. Certain facilities are guaranteed by an intermediate parent entity, in which case the parent entity must meet certain consolidated financial covenants under those term loan facilities including maintaining certain minimum tangible net worth, cash requirements and debt-to-asset ratios. Some of the facilities also have an interest and principal coverage ratio, debt service coverage and vessel value requirement for the subsidiary borrower. The Company was in compliance with these covenants as at December 31, 2020. (d) Senior unsecured notes: During the year ended December 31, 2019, the Company repaid April 2019 (e) Fairfax Notes: On February 28, 2020, the Company issued to Fairfax, in a private placement, $100,000,000 aggregate principal amount of senior notes, which bear interest at a fixed rate of 5.50% per annum and mature on March 1, 2027. The Fairfax Notes allow Fairfax to call for early redemption some or all of the Fairfax Notes on each respective anniversary date of issuance (the “Annual Put Right”) by providing written notice between 150 days and 120 days prior to each applicable anniversary date. In December 2020, Fairfax undertook not to exercise its Annual Put Right to call for early redemption of Fairfax Notes on their respective 2022 anniversary dates; the Fairfax Notes are not puttable to the Company until 2023. At any time on or after February 14, 2023, January 15, 2024 and January 15, 2025, the Company may elect to redeem all or any portion of the 2025 Notes, 2026 Notes and 2027 Fairfax Notes, respectively, at a price equal to 100% of the principal amount being redeemed. Interest payments on the Fairfax Notes are payable quarterly. The Fairfax Notes are guaranteed by certain of the Company’s subsidiaries and secured by ownership interest in other subsidiaries of the Company. (f) Exchangeable Notes: On December 21, 2020, the Company, through its wholly-owned subsidiary, Seaspan Corporation issued $201,250,000 aggregate principal amount of 3.75% exchangeable senior unsecured notes due 2025 (the “Exchangeable Notes”) in a private placement. The Exchangeable Notes are exchangeable at the holders’ option into an aggregate of 15,474,817 Atlas common shares at an initial exchange price of $13.005 per share, in equivalent cash or a combination of Atlas common shares and cash, as elected by the Company, on or after September 15, 2020, or earlier in the following circumstances: 12. Long-term debt (continued) (f) Exchangeable Notes (continued): • After December 31, 2020, if the last reported price of an Atlas common share is at least 130% of the exchange price then in effect over a specified measurement period; • If the trading price per $1,000 principal amount of Exchangeable Notes during a specified measurement period is less than 98% of the last reported sale price on Atlas common shares multiplied by the applicable exchange rate; and • Upon the occurrence of certain significant corporate events, or in response to early redemption elected by the Company. The exchange price is subject to anti-dilution and make-whole clauses. The holders may require the Company to redeem the Exchangeable Notes held by them upon the occurrence of certain corporate events qualifying as a fundamental change in the business. The Company may redeem the Exchangeable Notes in connection with certain tax-related events or on any business day on or after December 20, 2023 and prior to September 15, 2025, if the last reported sale price of an Atlas common share is at least 130% of the exchange price during a specified measurement period. A redemption of the Exchangeable Notes is made at 100% of the principal amount, plus accrued and unpaid interest. The Exchangeable Notes mature on December 15, 2025, unless earlier exchanged, repurchased or redeemed. Upon issuance, the proceeds from the Exchangeable Notes were allocated between debt, measured at fair value of $195,000,000 Capped Call Transactions In connection with the issuance of the Exchangeable Notes, the Company entered into capped call transactions with affiliates of certain of the initial purchasers of the Exchangeable Notes and other financial institutions, using $15,536,000 in proceeds from the issuance, to reduce the potential dilution to Atlas common shares upon any exchange of notes and/or offset any cash payments the Company is required to make upon exchange of the Exchangeable Notes, in excess of the principal amount. They may be settled in cash, shares, or a combination of cash and shares as determined by the settlement method of the Exchangeable Notes, at a strike price with underlying shares equal to that of the Exchangeable Notes and subject to anti-dilution adjustments substantially similar to those applicable to the Exchangeable Notes. The capped calls are exercisable up to a maximum price of $17.85 per share, subject to certain adjustments. The instruments expire on December 15, 2025.

Operating Lease Liabilities

Operating Lease Liabilities	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Operating lease liabilities	13. Operating lease liabilities: December 31, December 31, 2020 2019 Operating lease commitments $ 927.0 $ 1,107.6 Impact of discounting (141.5 ) (184.4 ) Impact of changes in variable rates 44.7 19.1 Operating lease liabilities 830.2 942.3 Current portion of operating lease liabilities (160.9 ) (159.7 ) Operating lease liabilities $ 669.3 $ 782.6 1 3 . Operating lease liabilities (continued) : Operating lease liabilities relate to vessel sale-leaseback transactions and other operating leases. Vessel sale-leaseback transactions under operating lease arrangements are in part, indexed to three month LIBOR, reset on a quarterly basis. For one of the Company’s vessel operating leases, an option to repurchase the vessel exists at the end of its lease term. For all other arrangements, the lease may be terminated prior to the end of the lease term, at the option of the Company, by repurchasing the respective vessels on a specified repurchase date at a pre-determined fair value amount. For one of these arrangements, if the Company elects not to repurchase the vessel, the lessor may choose not to continue the lease until the end of its term. Each sale-leaseback transaction contains financial covenants requiring the Company to maintain certain tangible net worth, interest coverage ratios and debt-to-assets ratios, as defined. Operating lease costs related to vessel sale-leaseback transactions and other leases are summarized as follows: Year ended December 31, 2020 Year ended December 31, 2019 Lease costs: Operating lease costs $ 166.5 $ 160.0 Variable lease adjustments (12.4 ) (3.0 ) Other information: Operating cash outflow used for operating leases 147.8 153.2 Weighted average discount rate 4.8 % 4.8 % Weighted average remaining lease term 7 years 8 years

Other Financing Arrangements

Other Financing Arrangements	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Other Financing Arrangements	14. Other financing arrangements: 2020 2019 Other financing arrangements $ 879.5 $ 513.8 Deferred financing fees (13.7 ) (5.3 ) Other financing arrangements 865.8 508.5 Current portion of other financing arrangements (64.1 ) (134.6 ) Other financing arrangements $ 801.7 $ 373.9 The Company, through certain of its wholly-owned subsidiaries, has entered into non-recourse or limited recourse sale-leaseback arrangements with financial institutions to fund the acquisition of vessels. Under these arrangements, the Company has agreed to transfer the vessels to the counterparties and lease the vessels back from the counterparties over the applicable lease term as a financing lease arrangement. In the arrangements where the shipbuilding contracts are novated to the counterparties, the counterparties assume responsibility for the remaining payments under the shipbuilding contracts. In certain of the arrangements, the counterparties are companies whose only assets and operations are to hold the Company’s leases and vessels. The Company operates the vessels during the lease term, supervises the vessels’ construction before the lease term begins, if applicable, and/or is required to purchase the vessels from the counterparties at the end of the lease term. As a result, in most cases, the Company is considered to be the primary beneficiary of the counterparties and consolidates the counterparties for financial reporting purposes. In all cases, these arrangements are considered failed-sales. The vessels are recorded as an asset and the obligations under these arrangements are recorded as a liability. The terms of the leases are as follows: 14. Other financing arrangements (continued): (i) COSCO Faith - 13100 TEU vessel: Under this arrangement, the counterparty has provided financing of $109,000,000. The 12-year lease term began in March 2012, which was the vessel’s delivery date. Lease payments include an interest component based on three month LIBOR plus a 3.0% margin. At the end of the lease, the Company will have the option to purchase the vessel from the lessor for $1. In January 2020, the Company made a prepayment of $48,316,000 on the remaining balance of the arrangement. (ii) Leases for three 4500 TEU vessels: Under these arrangements, the counterparty has provided refinancing of $150,000,000. The five year lease terms began in March 2015. At delivery, the Company sold and leased the vessels back over the terms of the sale-leaseback transactions. At the end of the lease terms, the Company is obligated to purchase the vessels at a pre-determined purchase price. The remaining balance was paid in March 2020. (iii) Leases for five 11000 TEU vessels: Under these arrangements, the counterparty has provided financing of $420,750,000. The 17-year lease terms began between August 2017 and January 2018, which were the vessels’ delivery dates. Lease payments include interest components based on three month LIBOR plus a 3.3% margin. At delivery, the Company sold and leased the vessels back over the term of the sale-leaseback transactions. At the end of the lease terms, the Company is obligated to purchase the vessels at a pre-determined purchase price. In October 2020, the Company made a prepayment of $71,084,000 on the remaining principal balance of one of the 11000 TEU vessels under sales-leaseback financing arrangement. (iv) Leases for four 12000 TEU vessels: Under these arrangements, the counterparty has provided financing of $337,732,000. The 10-year lease terms began in March and April 2020, which were the vessels’ delivery dates. Lease payments include interest components based on one month LIBOR plus a 2.75% margin. At delivery, the Company sold and leased the vessels back over the term of the sale-leaseback transactions. At the end of the lease terms, the Company is obligated to purchase the vessels at a pre-determined purchase price. (v) Leases for two 13000 TEU vessels: Under these arrangements, the counterparty has provided financing of $138,225,000. The 10-year lease terms began in August and September 2020, which were the vessels’ delivery dates. Lease payments include interest components based on three month LIBOR plus a 2.75% margin. At delivery, the Company sold and leased the vessels back over the term of the sale-leaseback transactions. At the end of the lease terms, the Company is obligated to purchase the vessels at a pre-determined purchase price. (vi) Leases for two 12000 TEU vessels: Under these arrangements, the counterparty has provided financing of $158,400,000. The 10-year and 12-year lease terms began in October and November 2020, respectively, which were the vessels’ delivery dates. Lease payments include interest components based on three month LIBOR plus a 2.75% margin. At delivery, the Company sold and leased the vessels back over the term of the sale-leaseback transactions. The Company has the option to purchase the vessels throughout their respective lease terms at a pre-determined purchase price The weighted average rate of interest, including the margin, was 3.12% at December 31, 2020 (2019 – 5.25%). 14. Other financing arrangements (continued): Based on amounts funded for other financing arrangements, payments due to lessors would be as follows: 2021 $ 64.6 2022 64.6 2023 64.6 2024 64.6 2025 57.4 Thereafter 563.7 $ 879.5

Other liabilities

Other liabilities	12 Months Ended
	Dec. 31, 2020
Other Liabilities Disclosure [Abstract]
Other liabilities	15. Other liabilities: 2020 2019 Asset retirement obligations (a) $ 42.3 $ — Other 23.4 19.0 Other long-term liabilities 65.7 19.0 Current portion of other long-term liabilities (24.8 ) (7.8 ) Other long-term liabilities $ 40.9 $ 11.2 ( a) Asset retirement obligations: Asset retirement obligations were assumed as part of the APR Energy acquisition and consist of the contractual requirement to demobilize the Company’s mobile power generation sites when there is a legal obligation associated with the demobilization and the fair value of the liability can be reasonably estimated. Asset retirement obligations, December 31, 2019 $ — Liabilities acquired 45.9 Liabilities incurred 5.3 Liabilities settled (6.6 ) Provision reassessment (2.9 ) Accretion expense 0.6 Asset retirement obligations, December 31, 2020 $ 42.3

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Tax	16. Income tax: The Company is tax resident in the United Kingdom and consists of its containership leasing and mobile power generation segments. The effective tax rate for its containership segment is nominal, primarily due to international shipping reciprocal exemptions. Its mobile power generation segment, acquired on February 28, 2020 through APR Energy, is subject to income taxes in multiple jurisdictions. Net earnings before income taxes for the year ended December 31, 2020 relates only to the foreign jurisdictions. Similarly, the Company’s income tax expense for the year ended December 31, 2020 related only to foreign jurisdictions and consists of the following: 2020 Current tax Domestic Foreign Total Current tax expense $ — $ 20.2 $ 20.2 $ — $ 20.2 $ 20.2 Deferred tax Deferred tax expense $ — $ (3.6 ) $ (3.6 ) $ — $ (3.6 ) $ (3.6 ) Total tax expense $ — $ 16.6 $ 16.6 As a result of the acquisition of APR Energy, the Company operates in countries that have differing tax laws and rates. Therefore, a consolidated weighted average tax rate will vary from year to year according to the source of earnings or losses by country and the change in applicable tax rates. Prior to the APR Energy acquisition, the Company was subject to nominal income taxes primarily due to international shipping reciprocal exemptions for the containership segment. For the year ended December 31, 2020, the reconciliation between the effective tax rate of 7.94% and the statutory UK income tax rate of 19.0% 2020 Computed "Expected" tax expense: Computed tax expense on income from continuing operations $ 39.7 Increase (reduction) in income taxes resulting from: Certain income from containership leasing segment that is exempt from tax (58.0 ) Goodwill impairment not deductible for tax 22.4 Change in valuation allowance 25.4 Change in current year uncertain tax positions 1.2 Change in tax law (0.1 ) Foreign rate differential (26.8 ) Withholding taxes 7.8 Other, net 5.0 $ 16.6 16. Income tax (continued): The deferred tax assets and liabilities were as follows for the year ended 31 December, 2020: Deferred tax assets 2020 Decommission provisions 16.6 Property, plant and equipment 25.9 Reserves and accrued expenses 63.9 Tax losses carried forward 40.4 Interest allowance 16.8 Deferred revenue 0.4 Valuation allowance (129.3 ) $ 34.7 Deferred tax liabilities 2020 Deferred job costs (3.8 ) Accelerated asset costs (2.7 ) Inflation adjustment (5.2 ) Other timing differences (3.7 ) $ (15.4 ) Net deferred tax asset $ 19.3 As at December 31, 2019, the Company did not have deferred tax assets and liabilities. The increase in the valuation allowances during the year ended December 31, 2020 primarily relates to an increase in net operating losses related to APR Energy since the acquisition date of February 28, 2020. Substantially all of the Company’s net operating losses have no expiry date. As at 31 December 2020, the Company has foreign tax Tax years that remain open to examination by some of the major jurisdictions in which the Company is subject to tax range from two to four years. As at December 31, 2020, the Company had income tax payable of $110,400,000 (2019 – nil). This balance includes cash taxes payable and a reserve for global uncertain tax positions. The Company’s uncertain tax positions relate primarily to items that were acquired as part of the APR Energy acquisition. Substantially all of these items are indemnified and a corresponding indemnification asset has been recorded (note 3). The total amount of unrecognized benefits on uncertain tax positions that, if recognized, would affect the Company’s effective tax rate by $1.2 million. The Company does not presently anticipate that its provisions for these uncertain tax positions will significantly increase in the next 12 months. The Company reviews its tax obligations regularly and may update its assessment of its tax positions based on available information at the time. 16. Income tax (continued) : The Company’s uncertain tax positions relate primarily to items that were acquired as part of the APR Energy acquisition. Substantially all of these items are indemnified and a corresponding indemnification asset has been recorded (note 3). The Company does not presently anticipate that its provisions for these uncertain tax positions will significantly increase in the next 12 months. The Company reviews its tax obligations regularly and may update its assessment of its tax positions based on available information at the time. The following table summarizes the activity related to the Company’s unrecognized tax benefits: 2020 Balance as of December 31, 2019 - Acquired as part of APR Energy acquisition (note 3) 75.4 Decreases due to tax provisions expired 1.2 Balance as of December 31, 2020 $ 76.6 As at December 31, 2019, the Company did not have unrecognized tax benefits. The Company recognizes interest expense and penalties related to unrecognized tax benefits as income tax expense. The Company had interest or penalties accrued in the consolidated balance sheet at December 31, 2020. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, permits net operating loss (“NOL”) carryovers and carrybacks to offset 100% of taxable income for taxable years beginning before 2021. In addition, the CARES Act allows NOLs incurred in 2018, 2019, and 2020 to be carried back to each of the five preceding taxable years to generate a refund of previously paid income taxes. The Company evaluated the impact of the CARES Act, and the NOL carryback provision of the CARES Act does not result in a material cash benefit to it.

Preferred shares and share capi

Preferred shares and share capital	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Preferred shares and share capital	1 7 . Preferred shares and share capital: (a) Common shares: On February 27, 2020, upon completion of the Reorganization, the common shares of Seaspan, the predecessor of Atlas, was exchanged for Atlas common shares on a one-for-one basis. The Company has 400,000,000 Class A common shares authorized at December 31, 2020, with a par value of $0.01 per share. On February 28, 2020, the Company issued 29,891,266 common shares and reserved 6,664,270 common shares for holdback as part of the consideration paid for the acquisition of the shares of APR Energy (note 3). Concurrent with the acquisition, the Company issued 775,139 common shares to Fairfax to settle APR Energy’s indebtedness to Fairfax at closing. During the year ended December 31, 2020, the Sellers returned 1,849,641 previously issued common shares to the Company and 557,139 Holdback Shares were cancelled. Of the common shares returned, 1,122,290 shares were permanently forfeited as part of post-closing purchase price adjustments. The remaining 727,351 shares are held in reserve as treasury shares. These shares may be issuable to the Sellers at a future date, subject to settlement of potential indemnified events. During the year ended December 31, 2020, 318,637 shares were released from holdback and issued to the Sellers. 17. Preferred shares and share capital (continued): (a) Common shares (continued): The Company has a dividend reinvestment program (“DRIP”) that allows interested shareholders to reinvest all or a portion of cash dividends received in the Company’s common shares. If new common shares are issued by the Company, the reinvestment price is equal to the average price of the Company’s common shares for the five days immediately prior to the reinvestment, less a discount. The discount rate is set by the Board of Directors and is currently 3.0%. If common shares are purchased in the open market, the reinvestment price is equal to the average price per share paid. (b) Preferred shares: As at December 31, 2020, the Company had the following preferred shares outstanding: Liquidation preference Shares Dividend rate Redemption by Company December December Series Authorized Issued per annum permitted on or after 2020 2019 D 20,000,000 5,093,728 7.95 % January 30, 2018 (1) 127.3 127.3 E 15,000,000 5,415,937 8.25 % February 13, 2019 (1) 135.4 135.4 G 15,000,000 7,800,800 8.20 % June 16, 2021 (1) 195.0 195.0 H 15,000,000 9,025,105 7.875 % August 11, 2021 (1) 225.6 225.6 I 6,000,000 6,000,000 8.00 % October 30, 2023 (1) 150.0 150.0 (1) Redeemable by the Company, in whole or in part, at a redemption price of $25.00 per share plus unpaid dividends. The preferred shares are not convertible into common shares and are not redeemable by the holder . The preferred shares are subject to certain financial covenants. The Company is in compliance with these covenants on December 31, 2020. (c) Warrants: The Company issued warrants to purchase 25,000,000 Class A common shares at an exercise price of $8.05 per share, subject to customary anti-dilution adjustments. Each warrant is exercisable within seven years. The holder may pay the aggregate exercise price by cash, by cashless exercise or by any combination of the foregoing. The Company can elect to require early exercise of the warrants, at any time after July 16, 2022, if the volume weighted average price of the Company’s Class A common shares, averaged over a 20-day period, equals or exceeds twice the exercise price of the warrants.

Earnings per share (_EPS_)

Earnings per share (“EPS”)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per share (“EPS”)	18. Earnings per share (“EPS”): Year ended December 31, 2020 For the year ended December 31, 2020 Earnings (numerator) Shares (denominator) Per share amount Net earnings 192.6 Less preferred share dividends: Series D (10.1 ) Series E (11.2 ) Series G (16.0 ) Series H (17.8 ) Series I (12.0 ) Basic EPS: Net earnings attributable to common shareholders $ 125.5 241,502,000 $ 0.52 Effect of dilutive securities: Share-based compensation — 541,000 Fairfax warrants — 3,096,000 Holdback shares — 5,375,000 Diluted EPS (1) Net earnings attributable to common shareholders $ 125.5 250,514,000 $ 0.50 (1) The Exchangeable Notes are not included in the computation of diluted EPS when their effects are anti-dilutive. Year ended December 31, 2019 For the year ended December 31, 2019 Earnings (numerator) Shares (denominator) Per share amount Net earnings $ 439.1 Less preferred share dividends: Series D (14.1 ) Series E (11.2 ) Series G (16.0 ) Series H (17.8 ) Series I (12.0 ) Basic EPS: Net earnings attributable to common shareholders $ 368.0 214,499,000 $ 1.72 Effect of dilutive securities: Share-based compensation — 471,000 Fairfax warrants — 4,902,000 Diluted EPS: Net earnings attributable to common shareholders $ 368.0 219,872,000 $ 1.67 18. Earnings per share (“EPS”) (continued): Year ended December 31, 2018 For the year ended December 31, 2018 Earnings (numerator) Shares (denominator) Per share amount Net earnings $ 278.8 Less preferred share dividends: Series D (14.6 ) Series E (11.2 ) Series F (8.3 ) Series G (16.0 ) Series H (17.8 ) Series I (3.4 ) Basic EPS: Net earnings attributable to common shareholders $ 207.5 154,848,000 $ 1.34 Effect of dilutive securities: Share-based compensation — 91,000 Fairfax warrants — 3,129,000 Diluted EPS (1) Net earnings attributable to common shareholders $ 207.5 158,068,000 $ 1.31 (1) The convertible Series F preferred shares are not included in the computation of diluted EPS when their effects are anti-dilutive.

Share-based compensation

Share-based compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation	19. Share-based compensation: In December 2005, Seaspan’s board of directors adopted the Seaspan Corporation Stock Incentive Plan, which was administered by Seaspan’s board of directors and, under which its officers, employees and directors could be granted options, restricted shares, phantom share units and other stock-based awards as determined by the Seaspan board of directors. Upon consummation of the Reorganization, Atlas assumed Seaspan’s equity-based compensation plans, including the Seaspan Corporation Stock Incentive Plan. Awards previously granted under the Seaspan Corporation Stock Incentive Plan are now exercisable for Atlas common shares instead of Seaspan common shares. In connection with the Reorganization, the Seaspan Plan was amended and restated as the Atlas Corp. Stock Incentive Plan (the “Atlas Plan”). In June 2020, the Atlas Plan was amended and restated to increase the number of common shares issuable under the Atlas Plan from 5,000,000 to 10,000,000. At December 31, 2020, there are 1,993,398 (2019 – 1,291,076) remaining shares left for issuance under this Plan. 19. Share-based compensation (continued): A summary of the Company’s outstanding restricted shares, phantom share units, stock appreciation rights (“SARs”) and restricted stock units as of and for the twelve months ended December 31, 2020, 2019, and 2018 are presented below: Restricted shares Phantom share units SARs Restricted stock units Stock options Number W.A. Number W.A. grant Number of W.A. grant Number W.A. grant Number W.A. grant of shares date FV of units date FV SARs date FV of units date FV of options date FV December 31, 2017 94,533 8.89 727,001 13.60 485,974 3.40 71,184 7.80 — — Granted 164,326 7.19 30,000 6.86 — — 609,248 8.18 500,000 2.45 Vested and exercised (119,509 ) 8.52 (113,333 ) 18.80 — — (83,220 ) 9.87 — — Expired — — — — (485,974 ) 3.40 — — — — Cancelled (53,608 ) 7.10 (76,666 ) 7.90 — — (12,441 ) 7.28 — — December 31, 2018 85,742 $ 7.28 567,002 $ 12.97 — $ — 584,771 $ 7.91 500,000 $ 2.45 Granted 67,400 8.15 — — — — 249,732 8.90 — — Vested and exercised (85,742 ) 7.28 (60,001 ) 16.68 — — (224,073 ) 8.59 — — Cancelled — — — — — — (33,466 ) 9.05 — — December 31, 2019 67,400 $ 8.15 507,001 $ 12.53 — $ — 576,964 $ 8.01 500,000 $ 2.45 Granted 1,051,492 7.84 — — — — 1,824,786 7.83 1,500,000 2.57 Vested and exercised (67,400 ) 8.15 (20,000 ) 6.85 — — (313,231 ) 9.32 — — Cancelled — — — — — — (79,635 ) 9.84 — — December 31, 2020 1,051,492 $ 7.84 487,001 $ 12.76 — $ — 2,008,884 $ 7.57 2,000,000 $ 2.51 Vested and exercisable, December 31, 2020 — $ — 487,001 $ 12.76 — $ — — $ — 200,000 $ 2.54 During the year ended December 31, 2020, the Company amortized At December 31, 2020, there was $22,334,000 (2019 – $3,764,000) of total unamortized compensation costs relating to unvested share-based compensation awards, which are expected to be recognized over a weighted-average period of 29 months (a) Restricted shares and phantom share units: Common shares are issued on a one-for-one basis in exchange for the cancellation of vested and exchanged phantom share units. The restricted shares generally vest over one year and the phantom share units generally vest over three years. During the year ended December 31, 2020, the Company granted 1,051,492 restricted shares to its board of directors. 1,000,000 restricted shares have requisite service periods ending on December 31, 2022. The remaining 51,492 restricted shares vest on January 1, 2021. (b) Restricted stock units: The restricted stock units generally vest over two or five years, in equal tranches. Upon vesting of the restricted stock units, the participant will receive common shares. In June 2020, the Company granted the Chief Executive Officer (“CEO”) 1,500,000 restricted stock units. The restricted stock units vest in five tranches annually over five years beginning December 31, 2021 and have a grant date fair value of $7.25 per unit. In September 2020, 71,799 restricted stock units previously issued to an executive officer of the Company were forfeited. 19. Share-based compensation (continued): (c) Stock options: In January 2018, the Company granted the CEO stock options to acquire 500,000 Class A common shares at an exercise price of $7.20 per share. The stock options vest equally on each of the first five anniversaries of the CEO’s start date in January 2018 In June 2020, the Company granted the CEO stock options to acquire 1,500,000 common shares at an exercise price of $7.80 per share. The stock options vest in five tranches annually over five years beginning December 31, 2021 and expire on June 24, 2030.

Other information

Other information	12 Months Ended
	Dec. 31, 2020
Additional Financial Information Disclosure [Abstract]
Other information	20. Other information: (a) Accounts payable and accrued liabilities: The principal components of accounts payable and accrued liabilities are: 2020 2019 Accrued interest $ 17.2 $ 17.1 Accounts payable and other accrued liabilities 116.9 66.3 $ 134.1 $ 83.4 20. Other information (continued): (b) Supplemental cash flow information: 2020 2019 2018 Interest paid $ 156.2 $ 183.1 $ 194.3 Interest received 5.0 8.9 3.7 Undrawn credit facility fee paid 0.8 1.7 0.6 Income taxes paid 16.8 — — Non-cash investing and financing transactions: Dividend reinvestment 0.3 1.2 22.8 Arrangement and transaction fee settled in shares — — 2.3 Commencement of sales-type lease 57.0 316.7 — Carrying value of previously held equity in GCI settled on acquisition — — 61.9 Issuance of common shares on GCI acquisition — — 13.9 Issuance of warrants — — 67.5 Issuance of Series D preferred shares on GCI acquisition — — 47.2 Settlement of GCI transaction fees paid by the Company — — 15.2 Settlement of loans to affiliate, accrued interest and other intercompany balances on GCI acquisition — — 38.8 APR Energy loans settled in shares 8.3 — — Common shares issued on APR Energy acquisition 316.8 — — Holdback Shares reserved on APR Energy acquisition 70.6 — — Purchase price adjustment related to APR Energy acquisition 4.5 — — Reclassification on lease modification 377.4 — — Contingent consideration asset related to APR Energy acquisition 95.2 — — Net assets acquired on APR Energy acquisition 287.7 — — ARO liabilities incurred 5.3 — — ARO provision re-assessment 2.9 — — Refinancing of existing term loan credit facilities with draws made on new debt — 302.7 — Right-of-use assets arising from new operating leases 1.2 0.7 — Cancellation of common shares issued on APR Energy acquisition 12.5 — — Prepayments transferred to property, plant and equipment upon vessel delivery 46.8 — — Changes in operating assets and liabilities Accounts receivable (17.1 ) (2.3 ) 15.5 Inventories (5.9 ) 6.3 0.5 Prepaids expenses and other (10.3 ) (0.9 ) 17.0 Net investment in lease 13.3 9.3 44.3 Accounts payable and accrued liabilities (16.4 ) 11.5 (7.0 ) Settlement of decommissioning provisions (5.9 ) — — Deferred revenue 8.4 (0.6 ) (46.8 ) Income tax payable 3.9 — — Major maintenance (54.6 ) (22.3 ) (10.3 ) Other liabilities (8.6 ) — (1.5 ) Operating lease liabilities (114.7 ) (111.9 ) — Derivative instruments 22.5 55.0 42.0 Contingent consideration asset 18.7 — — 20. Other information (continued): The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the amounts shown in the consolidated statements of cash flows: 2020 2019 2018 Cash and cash equivalents $ 304.3 $ 195.0 $ 357.3 Restricted cash included in prepaid and other — 2.3 — Restricted cash included in other assets (note 11) 38.2 — 14.1 Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows $ 342.5 $ 197.3 $ 371.4

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and contingencies	21. Commitments and contingencies: (a) Operating leases: At December 31, 2020, the commitment under operating leases for vessels is $917,130,000 for 2021 to 2029 and for other leases is $9,893,000 for 2021 to 2024. Total commitments under these leases are as follows: 2021 $ 147.1 2022 143.1 2023 144.6 2024 147.8 2025 125.7 Thereafter 218.7 $ 927.0 For operating leases indexed to three month LIBOR, commitments under these leases are calculated using the LIBOR in place as at December 31, 2020 for the Company. (b) Vessels under construction: In November 2020, the Company entered into agreements to build five 12200 TEU containerships for an aggregate purchase price of $419,825,000, net of address commissions. The amount is payable in four installments. As of December 31, 2020, $41,982,500, net of address commissions relating to the first installment was paid. The Company has outstanding commitments for the remaining installment payments as follows: 2021 $ 142.7 2022 235.1 Total $ 377.8 (c) Letter of credit: As at December 31, 2020, the Company has $11,686,000

Financial instruments

Financial instruments	12 Months Ended
	Dec. 31, 2020
Financial Instruments [Abstract]
Financial instruments	22. Financial instruments: (a) Fair value: The carrying values of cash and cash equivalents, short-term investments, restricted cash, accounts receivable, income tax payable, accounts payable and accrued liabilities approximate their fair values because of their short term to maturity. As of December 31, 2020, the fair value of the Company’s revolving credit facilities and term loan credit facilities, excluding deferred financing fees is $2,827,984,000 (2019 - $2,624,711,000) and the carrying value is $2,866,850,000 (2019 - $2,666,274,000). As of December 31, 2020, the fair value of the Company’s operating lease liabilities is $828,111,000 (2019 - $940,034,000) and the carrying value is $830,200,000 (2019 - $942,308,000). As of December 31, 2020, the fair value of the Company’s other financing arrangements, excluding deferred financing fees, is $891,710,000 (2019 - $553,754,000) and the carrying value is $879,468,000 (2019 - $513,771,000). The fair value of the revolving and term loan credit facilities, operating lease liabilities and other financing arrangements, excluding deferred financing fees, is estimated based on expected principal repayments and interest, discounted by relevant forward rates plus a margin appropriate to the credit risk of the Company. Therefore, the Company has categorized the fair value of these financial instruments as Level 2 in the fair value hierarchy. As of December 31, 2020, the fair value of the Company’s senior unsecured notes is $89,207,000 (2019 – $82,816,000) and the carrying value is $80,000,000 (2019 – $80,000,000). The aggregate fair value of the 2025 Notes and 2026 Notes was $538,083,000 (2019 – $525,591,000) and the aggregate carrying value was $500,000,000 (2019 - $500,000,000) or $369,100,000 (2019 – $349,106,000), net of discount. In February 2020, the Company issued the 2027 Notes. The fair value of the 2027 Fairfax Notes was $101,975,000 and the carrying value was $100,000,000. In December 2020, the Company issued the Exchangeable Notes. The fair value of the Company’s Exchangeable Notes is $195,232,000 and the carrying value is $201,250,000 or $195,000,000, net of debt discount. The fair value is calculated using the present value of expected principal repayments and interest discounted by relevant forward rates plus a margin appropriate to the credit risk of the Company. As a result, these amounts are categorized as Level 2 in the fair value hierarchy. The Annual Put Right features included in the 2025 Notes and 2026 Notes are considered embedded derivatives that are separately accounted for and are re-measured at fair value at the end of each reporting period. The fair value of the derivative put instruments at each reporting period is derived from the difference between the fair value of the notes and the fair value of a similar debt without Annual Put Rights, which are calculated using a trinomial tree. The assumptions used include an estimate of the risk-free yield curve, interest volatility and a company-specific credit risk. The fair values derivative put instruments are determined based on interest rate inputs that are unobservable. Therefore, the Company has categorized the fair value of these derivative financial instruments as Level 3 in the fair value hierarchy. The Annual Put Right feature included in the 2027 Fairfax Notes, issued at par value, is not considered an embedded derivative. The Company’s interest rate derivative financial instruments are re-measured to fair value at the end of each reporting period. The fair values of the interest rate derivative financial instruments have been calculated by discounting the future cash flow of both the fixed rate and variable rate interest rate payments. The discount rate was derived from a yield curve created by nationally recognized financial institutions adjusted for the associated credit risk. The fair values of the interest rate derivative financial instruments are determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets. Therefore, the Company has categorized the fair value of these derivative financial instruments as Level 2 in the fair value hierarchy. 2 2 . Financial instruments (continued): (a) Fair value (continued): As part of the acquisition of APR Energy, the Company obtained a contingent consideration asset related to compensation the Company will receive from the Sellers on losses that may be generated from cash repatriation from a foreign jurisdiction. The fair values of the contingent consideration asset at acquisition and at December 31, 2020 are calculated as the present value of expected future compensable losses from conversion of cash from foreign currency to US dollars, derived from the discount expected to be realized on repatriation of cash from the foreign jurisdiction over a specified period of time, which is a significant unobservable input. As such, the Company has categorized the fair value of the contingent consideration asset as Level 3 in the fair value hierarchy. The discount expected to be realized on repatriation of cash as of December 31, 2020 is 45%. An increase of 5% on the discount would result in an increase in fair value of approximately $3,330,000. A decrease of 5% on the discount would result in a decrease in fair value of approximately $3,330,000. As part of the acquisition of APR Energy, the Company also obtained, subject to definitive documentation, a contingent consideration asset related to compensation the Company expects to receive from Fairfax on losses realized on future sale or disposal of certain property, plant and equipment and inventory items. The fair values of the contingent consideration asset at acquisition and at December 31, 2020 are determined based on the present value of expected future compensation, calculated as the difference between the book value of the respective assets at acquisition and the realizable value of the asset obtained from market quotes, which is a significant unobservable input. As such, the Company has categorized the fair value of the contingent consideration asset as Level 3 in the fair value hierarchy. Unobservable inputs for recurring and non-recurring Level 3 disclosures are obtained from third parties whenever possible and reviewed by the Company for reasonableness. (b) Interest rate swap derivatives: The Company uses interest rate derivative financial instruments, consisting of interest rate swaps to manage its interest rate risk associated with its variable rate debt. If interest rates remain at their current levels, the Company expects that $25,966,000 would be settled in cash in the next 12 months on instruments maturing after December 31, 2020. The amount of the actual settlement may be different depending on the interest rate in effect at the time settlements are made. On August 30, 2019, one of the Company’s interest rate swap counterparties exercised its termination right for early settlement. Upon termination, the Company made a payment of $97,955,000, equal to the fair value liability at the date of settlement, plus an additional amount in accrued interest. As of December 31, 2020, the Company had the following outstanding interest rate derivatives: Fixed per annum rate swapped for LIBOR Notional amount as of December 31, 2020 Maximum notional amount (1) Effective date Ending date 5.4200% $ 302.3 $ 302.3 September 6, 2007 May 31, 2024 1.6490% 160.0 160.0 September 27, 2019 May 14, 2024 0.7270% 125.0 125.0 March 26, 2020 March 26, 2025 0.7800% 125.0 125.0 March 23, 2020 March 23, 2025 1.6850% 110.0 110.0 November 14, 2019 May 15, 2024 5.6000% 93.6 93.6 June 23, 2010 December 23, 2021 (2) 1.4900% 29.4 29.4 February 4, 2020 December 30, 2025 (1) Over the term of the interest rate swaps, the notional amounts increase and decrease. These amounts represent the peak notional amount over the remaining term of the swap. (2) Prospectively de-designated as an accounting hedge in 2008. 22. Financial instruments (continued): ( c ) Financial instruments measured at fair value: The following provides information about the Company’s financial instruments measured at fair value: 2020 2019 Contingent consideration asset $ 90.9 $ — Fair value of derivative liabilities Interest rate swaps 63.0 49.3 Derivative put instrument — 0.9 There are no amounts subject to the master netting arrangements in 2020 or 2019. The following table provides information about gains and losses included in net earnings and reclassified from accumulated other comprehensive loss (“AOCL”) into earnings: 2020 2019 2018 Earnings (losses) recognized in net earnings: Loss on interest rate swaps (1) $ (36.4 ) $ (58.8 ) $ 14.7 Gain on derivative put instrument 0.9 23.7 0.8 Gain on contingent consideration asset 6.8 — — Loss reclassified from AOCL to net earnings (2) Interest expense (0.3 ) (0.3 ) (0.3 ) Depreciation and amortization (1.0 ) (0.7 ) (0.8 ) (1) For the years ended December 31, 2020, 2019 and 2018, cash flows related to actual settlement of interest rate swaps were $21,789,000, $126,782,000 and $41,284,000 respectively. These are included in investing activities on the consolidated statements of cash flows. For the years ended December 31, 2018, cash flows related to actual settlement of interest rate swaps of $41,284,000 was reclassified from operating activities to investing activities to conform with current financial statement presentation. (2) The effective portion of changes in unrealized loss on interest rate swaps was recorded in accumulated other comprehensive loss until September 30, 2008 when these contracts were voluntarily de-designated as accounting hedges. The amounts in accumulated other comprehensive loss are recognized in earnings when and where the previously hedged interest is recognized in earnings. The estimated amount of AOCL expected to be reclassified to net earnings within the next 12 months is approximately $1,094,000.

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent events	23. Subsequent events: (a) On January 4, 2021, the Company declared quarterly dividends of $0.496875, $0.515625, $0.512500, $0.492188 and $0.500000 per Series D, Series E, Series G, Series H and Series I preferred share, respectively, representing a total distribution of $16,763,000 to all shareholders of record on January 29, 2021. (b) On January 4, 2021, the Company declared a quarterly dividend of $0.125 per common share to all shareholders of record as of January 20, 2021. (c) In January 2021, the Company made repayment of $69,166,000 upon early termination of a sale-leaseback financing arrangement secured by 11000 TEU vessel. In March 2021, the Company entered into a new sales-leaseback financing arrangement of $83,700,000, secured by the same 11000 TEU vessel. (d) In February 2021, the Company issued $200,000,000 of senior unsecured sustainability-linked notes in the Nordic bond market. The notes will mature in February 2024 (e) In February 2021, the Company entered into shipbuilding contracts for the construction of two 24000 TEU ultra-modern containership newbuilds for an aggregate purchase price of $287,400,000, net of commissions receivable. (f) In February 2021, the Company entered into shipbuilding contracts for the construction of ten 15000 TEU dual-fuel liquefied natural gas containership newbuilds, including a firm purchase of five vessels and an option to construct an additional five similar vessels. In March 2021, the Company exercised the option to construct the additional five similar vessels. The aggregate purchase price of the ten vessels is $1,399,010,000, net of commissions receivable. (g) In February 2021, the Company entered into shipbuilding contracts for the construction of twelve high-quality newbuild scrubber-fitted containerships, including firm orders for four 12000 TEU, and four 15000 TEU, plus an option for four additional 15000 TEU vessels. The aggregate purchase price of the eight firm order vessels is $806,400,000, net of address commissions. (h) In February 2021, the Company entered into an agreement to acquire two young, high-quality 15000 TEU scrubber-fitted containerships for an aggregate purchase price of $254,000,000. The vessels and the attached charters are expected to be delivered in the second quarter of 2021. (i) In March 2021, the Company entered into shipbuilding contracts for the construction of six 15000 TEU scrubber-fitted newbuild containerships for an aggregate purchase price of $697,800,000, net of address commissions.

Significant accounting polici_2

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of preparation	(a) Basis of preparation: The Reorganization was accounted for as a transaction among entities under common control under the pooling of interest method and represented a change in reporting entity whereby the financial information of Seaspan prior to the Reorganization was assumed by Atlas on a carry-over basis. Accordingly, the accompanying consolidated financial statements represent the consolidated historical operations and changes in consolidated financial position of Seaspan, which included the Company as a consolidated subsidiary from its incorporation on October 1, 2019 to February 27, 2020 and those of the Company thereafter, following the Reorganization. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America and the following accounting policies have been consistently applied in the preparation of the consolidated financial statements.
Principles of consolidation	(b) Principles of consolidation: The accompanying consolidated financial statements include the accounts of Atlas Corp. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated upon consolidation. The Company also consolidates any variable interest entities (“VIEs”) of which it is the primary beneficiary. The primary beneficiary is the enterprise that has both the power to make decisions that most significantly affect the economic performance of the VIE and has the right to receive benefits or the obligation to absorb losses that in either case could potentially be significant to the VIE. The impact of the consolidation of these VIEs is described in note 14. The Company accounts for its investment in companies in which it has significant influence by the equity method. The Company’s proportionate share of earnings is included in earnings and added to or deducted from the cost of the investment.
Foreign currency translation	(c) Foreign currency translation: The functional and reporting currency of the Company is the United States dollar. Transactions involving other currencies are converted into United States dollars using the exchange rates in effect at the time of the transactions. At the balance sheet date, monetary assets and liabilities that are denominated in currencies other than the United States dollar are translated into United States dollars using exchange rates at that date. Exchange gains and losses are included in net earnings.
Cash equivalents	(d) Cash equivalents: Cash equivalents include highly liquid securities with terms to maturity of three months or less when acquired.
Inventories	(e) Inventories: Inventories consist primarily of spare parts and consumables. Inventories are stated at the lower of cost or net realizable value. Inventory cost is primarily determined using average or weighted average cost method, depending on the nature of the inventory. Net realizable value is the estimated selling price in the ordinary course of business less costs to complete, disposal and transportation.
Property, plant and equipment	(f) Property, plant and equipment: Vessels Except as described below, vessels are recorded at their cost, which consists of the purchase price, acquisition and delivery costs, less accumulated depreciation. Vessels purchased from Seaspan’s predecessor upon completion of Seaspan’s initial public offering in 2005 were initially recorded at the predecessor’s carrying value. Depreciation is calculated on a straight-line basis over the estimated useful life of each vessel, which is 30 years from the date of completion. The Company calculates depreciation based on the estimated remaining useful life and the expected salvage value of the vessel. Power generating equipment Power generating equipment are recorded at their costs, which represent its original cost at the time of purchase, less accumulated depreciation. Costs incurred to mobilize and install power-generating equipment pursuant to a contract for the provision of power generation services are recorded in property, plant and equipment and are depreciated on a straight-line basis over the non-cancellable lease term to which the power generating equipment relates. A summary of the useful lives used for calculating depreciation and amortization is as follows: Turbines 25 years Generators 15 years Transformers 15 years Property, plant and equipment that are held for use are evaluated for impairment when events or circumstances indicate that their carrying amounts may not be recoverable from future undiscounted cash flows. Such evaluations include the comparison of current and anticipated operating cash flows, assessment of future operations and other relevant factors. If the carrying amount of the property, plant and equipment exceeds the estimated net undiscounted future cash flows expected to be generated over the asset’s remaining useful life, the carrying amount of the asset is reduced to its estimated fair value.
Vessel dry-dock activities	(g) Vessel dry-dock activities: Classification society rules require that vessels be dry-docked for inspection including planned major maintenance and overhaul activities for ongoing certification. The Company generally dry-docks its vessels once every five years. Dry-docking activities include the inspection, refurbishment and replacement of steel, engine components, electrical, pipes and valves, and other parts of the vessel. The Company uses the deferral method of accounting for dry-dock activities whereby capital costs incurred are deferred and amortized on a straight-line basis over the period until the next scheduled dry-dock activity.
Business combinations	(h) Business combinations: Business combinations are accounted for under the acquisition method. The acquired identifiable net assets are measured at fair value at the date of acquisition. Deferred taxes are recognized for any differences between the fair value of net assets acquired and the related tax basis. Any excess of the purchase price over the fair value of net assets acquired is recognized as goodwill. Associated transaction costs are expensed as incurred.
Goodwill	(i) Goodwill: Goodwill represents the excess of the purchase price of an acquired enterprise over the fair value assigned to assets acquired and liabilities assumed in a business combination. Goodwill is not amortized, but reviewed for impairment annually or more frequently if impairment indicators arise. When goodwill is reviewed for impairment, the Company may elect to assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. Alternatively, the Company may bypass this step and use a fair value approach to identify potential goodwill impairment and, when necessary, measure the amount of impairment. The Company uses a discounted cash flow model to determine the fair value of reporting units, unless there is a readily determinable fair market value.
Asset retirement obligations	(j) Asset retirement obligations: The Company records a provision and a corresponding long-lived asset for asset retirement obligations (“ARO”) when there is a legal obligation associated with the retirement of long-lived assets and the fair value of the liability can be reasonably estimated. The fair value of the ARO is measured using expected future cash flows discounted at the Company’s credit-adjusted risk-free interest rate. The liability is accreted up to the cost of retirement through interest expense over the non-cancellable lease term. The long-lived asset is depreciated straight-line over the same period. Changes in the amount or timing of the estimated ARO are recorded as an adjustment to the related asset and liability.
Deferred financing fees	(k) Deferred financing fees: Deferred financing fees represent the unamortized costs incurred on issuance of the Company’s credit facilities and other financing arrangements and are presented as a direct deduction from the related debt liability when available. Amortization of deferred financing fees on credit facilities is provided on the effective interest rate method over the term of the facility based on amounts available under the facilities. Amortization of deferred financing fees on other financing arrangements is provided on the effective interest rate method over the term of the underlying obligation. Amortization of deferred financing fees is recorded as interest expense.
Revenue	( l ) Revenue: Containership leasing revenue The Company derives revenue from the charter of its containership vessels. Each charter agreement is evaluated and classified as an operating lease or financing lease based on the lease term, fair value associated with the lease and any purchase options or obligations. The assessment is done at lease commencement and reassessed only when a modification occurs that is not considered a separate contract. Charters classified as operating leases include a lease component associated with the use of the vessel and a non-lease component related to vessel management. Total consideration in the lease agreement is allocated between the lease and non-lease components based on their relative standalone selling prices. For arrangements where the timing and pattern of transfer to the lessee is consistent between the lease and non-lease components and the lease component, if accounted for separately, would be classified as an operating lease, the Company has elected to treat the lease and non-lease components as a single lease component. Revenue is recognized each day the vessels are on-hire, managed and performance obligations are satisfied. 2. Significant accounting policies (continued): (l) Revenue (continued): Containership leasing revenue (continued): For charters that are classified as direct financing leases and sales-type leases, the present value of minimum lease payments and any unguaranteed residual value are recognized as net investment in lease. The discount rate used in determining the present values is the interest rate implicit in the lease. The lower of the fair value of the vessel based on information available at lease commencement date and the present value of the minimum lease payments computed using the interest rate implicit specific to each lease, represents the price, from which the carrying value of the vessel and any initial direct costs are deducted in order to determine the selling profit or loss. For financing leases that are classified as direct financing leases, the unearned lease interest income including any selling profit and initial direct costs are deferred and amortized to income over the period of the lease so as to produce a constant periodic rate of return on the net investment in lease. Any selling loss is recognized at lease commencement date. For financing leases that are classified as sales-type leases, any selling profit or loss is recognized at lease commencement date. Initial direct costs are expensed at lease commencement date if the fair value of the vessel is different from its carrying amount. If the fair value of the vessel is equal to its carrying amount, initial direct costs should be deferred and amortized to income over the term of the lease. Power generation revenue The Company also derives revenue from lease and service contracts that provide customers with comprehensive power generation services that include leasing of the power generation equipment, installation and dismantling services, operations and maintenance of the power generating equipment (“O&M”), operations monitoring and logistical support. The Company earns a fixed portion of revenue on these contracts by providing megawatt capacity to its customers. Each power equipment lease contract may, depending on its terms, contain a lease component, a non-lease component or both. Lease classification is determined on a contract-specific basis. Total consideration in contracts that include a lease component associated with the use of the power-generation equipment and a non-lease component related to O&M is allocated between the lease and non-lease components based on their relative standalone selling prices. For arrangements where the timing and pattern of transfer to the lessee is consistent between the lease and non-lease components and the lease component, if accounted for separately, would be classified as an operating lease, the Company has elected to treat the components as a single lease component. Revenue is recognized over the period in which the equipment is available to the customer for use and service is provided to the customer. Certain contracts provide for mobilization and decommissioning payments. Mobilization revenue received up front is deferred and recognized as revenue on a straight-line basis over the term of the contract. Decommissioning revenue is recognized ratably over the term of the contract, as it is earned.
Leases	(m) Leases: Leases classified as operating leases, where the Company is the lessee, are recorded as lease liabilities based on the present value of minimum lease payments over the lease term, discounted using the lessor’s rate implicit in the lease for each individual lease arrangement or the Company’s incremental borrowing rate, if the lessor’s implicit rate is not readily determinable. The lease term includes all periods covered by renewal and termination options where the Company is reasonably certain to exercise the renewal options or not to exercise the termination options. Corresponding right-of-use assets are recognized consisting of the lease liabilities, initial direct costs and any lease incentive payments. (m) Leases (continued): Lease liabilities are drawn down as lease payments are made and right-of-use assets are depreciated over the term of the lease. Operating lease expenses are recognized on a straight-line basis over the term of the lease, consisting of interest accrued on the lease liability and depreciation of the right-of-use asset, adjusted for changes in index-based variable lease payments in the period of change. Lease payments on short-term operating leases with lease terms of twelve months or less are expensed as incurred. Transactions are accounted for as sale-leaseback transactions when control of the asset is transferred. For sale-leaseback transactions, where the Company is the seller-lessee, any gains or losses on sale are recognized upon transfer.
Derivative financial instruments	(n) Derivative financial instruments: From time to time, the Company utilizes derivative financial instruments. All of the Company’s derivatives are measured at their fair value at the end of each period. Derivatives that mature within one year are classified as current. For derivatives not designated as accounting hedges, changes in their fair value are recorded in earnings. The Company’s hedging policies permit the use of various derivative financial instruments to manage interest rate risk. The Company had previously designated certain of its interest rate swaps as accounting hedges and applied hedge accounting to those instruments. By September 30, 2008, the Company de-designated all of the interest rate swaps it had accounted for as hedges to that date. Subsequent to their de-designation dates, changes in their fair value are recorded in earnings. The Company evaluates whether the occurrence of any of the previously hedged interest payments are considered to be remote. When the previously hedged interest payments are not considered remote of occurring, unrealized gains or losses in accumulated other comprehensive income associated with the previously designated interest rate swaps are recognized in earnings when and where the interest payments are recognized. If such interest payments are identified as being remote, the accumulated other comprehensive income balance pertaining to these amounts is reversed through earnings immediately.
Income taxes	(o) Income taxes: The Company accounts for income taxes using the asset and liability method. Under the liability method, deferred tax assets and liabilities are recognized for the anticipated future tax effects of temporary differences between the accounting basis and the tax basis of the Company’s assets and liabilities using the applicable jurisdictional tax rates. A valuation allowance for deferred tax assets is recorded when it is more likely than not that some or all of the benefit from the deferred tax asset will not be realized. The Company recognizes the tax benefits of uncertain tax positions only if it is more-likely-than-not that a tax position taken or expected to be taken in a tax return will be sustained upon examination by the taxing authorities, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense in the Company's consolidated statements of operations.
Share-based compensation	(p) Share-based compensation: The Company grants phantom share units, restricted shares, restricted stock units and stock options to certain of its officers, members of management and directors as compensation. Compensation cost is measured at the grant date fair values as follows: • Restricted shares, phantom share units and restricted stock units are measured based on the quoted market price of the Company’s common shares on the date of the grant. • Stock options are measured at fair value using the Black-Scholes model. The fair value of each grant is recognized on a straight-line basis over the requisite service period. The Company accounts for forfeitures in share-based compensation expense as they occur.
Fair value measurement	(q) Fair value measurement: Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e. the “exit price”) in an orderly transaction between market participants at the measurement date. The hierarchy is broken down into three levels based on the observability of inputs as follows: • Level 1 — Valuations based on quoted prices in active markets for identical assets or liabilities that the Company has the ability to access. Valuation adjustments and block discounts are not applied to Level 1 instruments. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of these products does not entail a significant degree of judgment. • Level 2 — Valuations based on one or more quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly. • Level 3 — Valuations based on inputs that are unobservable and significant to the overall fair value measurement.
Earnings per share	(r) Earnings per share: The treasury stock method is used to compute the dilutive effect of the Company’s share-based compensation awards, warrants and convertible instruments, where the presumption of share settlement has been overcome. Under this method, the incremental number of shares used in computing diluted earnings per share (“EPS”) is the difference between the number of shares assumed issued and purchased using assumed proceeds. The if-converted method is used to compute the dilutive effect of the Company’s convertible instruments where the presumption of share settlement has not been overcome. Under the if-converted method, the instruments are assumed to have been converted at the share price applicable at the end of the period, if dilutive. Contingently issuable shares are included in diluted EPS as of the beginning of the period, if contingencies are satisfied by the end of the period. If contingencies have not been satisfied by the end of the period, the number of contingently issuable shares included in diluted EPS is based on the number of shares, if any, that would be issuable if the end of the reporting period were the end of the contingency period, if the result is dilutive. The cumulative dividends applicable to the Series D, E, G, H and I preferred shares reduce the earnings available to common shareholders, even if not declared.
Use of estimates	(s) Use of estimates (continued): • reported amounts of assets and liabilities, • disclosure of contingent assets and liabilities at the balance sheet dates; and • reported amounts of revenue and expenses during the reporting fiscal periods. Areas where accounting judgments and estimates are significant to the Company and where actual results could differ from those estimates, include, but are not limited to the: • assessment of going concern; • assessment of property, plant and equipment useful lives; • expected salvage values; • recoverability of the carrying value of property, plant and equipment and intangible assets with finite lives which are subject to future market events; • carrying value of goodwill; • fair values of assets acquired and liabilities assumed from business combination; • fair value of asset retirement obligations; and • fair value of interest rate swaps, other derivative financial instruments and contingent consideration asset.
Comparative information	(t) Comparative information: Certain information has been reclassified to conform to the financial statement presentation adopted for the current year.
Recent accounting pronouncements	(u) Recently adopted accounting pronouncement: Leases Effective January 1, 2019, the Company adopted ASU 2016-02, “Leases”, using the modified retrospective method, whereby a cumulative effect adjustment was made as of the date of initial application. The Company elected the practical expedient to use the effective date of adoption as the date of initial application. Accordingly, financial information and disclosures in the comparative period were not restated. It also elected to apply the package of practical expedients such that for any expired or existing leases, it did not reassess lease classification, initial direct costs or whether the relevant contracts are or contain leases. The Company did not use hindsight to reassess lease term for the determination of impairment of right-of-use assets. The impacts of the adoption of ASU 2016-02 are as follows: (in millions of US dollars) As reported at December 31, 2018 Adjustments Adjusted at January 1, 2019 Right-of-use assets (1) (2) $ — $ 1,068.3 $ 1,068.3 Other assets (2) 204.9 (17.3 ) 187.6 Accounts payable and accrued liabilities (1) 70.2 (2.5 ) 67.7 Current portion of operating lease liabilities (1) — 160.2 160.2 Current portion of other long-term liabilities (3) 32.2 (22.2 ) 10.0 Operating lease liabilities (1) — 893.3 893.3 Other long-term liabilities (3) 181.1 (158.9 ) 22.2 Deficit (3) (645.6 ) 181.1 (464.5 ) ___________________ (1) Upon adoption of ASU 2016-02, the Company recorded non-cash right-of-use assets and operating lease liabilities on the balance sheet for its vessel sale-leaseback transactions and office leases under operating lease arrangements. Prior to January 1, 2019, operating leases were not included on the balance sheet and were recorded as operating lease expenses when incurred. The amount recognized as operating lease liabilities was based on the present value of future minimum lease payments, discounted using the lessor’s rate implicit in the lease or the Company’s incremental borrowing rate if the lessor’s implicit rate is not readily determinable and includes any existing accrued payments related to lease liabilities. Minimum lease payments referenced to an indexed rate were determined based on the respective rates at the adoption date. (2) Initial direct costs related to the Company’s vessel sale-leaseback transactions under operating lease arrangements were reclassified from other assets to right-of-use assets. (3) Deferred gain related to the Company’s vessel sale-leaseback transactions was recognized through deficit on the initial date of application. The accounting for lessors is largely unchanged under ASU 2016-02. The Company evaluated its lessor arrangements and determined that the amounts recognized and the pattern of recognition remained substantially the same as existing guidance which was previously used. Leases are classified as operating leases or financing leases based on the lease term and fair value associated with the lease. The assessment is done at lease commencement and reassessed only when a modification occurs that is not considered a separate contract. Measurement of credit loss Effective January 1, 2020, the Company adopted Accounting Standards Update (“ASU”) 2016-13, “Measurement of Credit Loss on Financial Instruments”. ASU 2016-13 replaces the current incurred loss impairment methodology with the expected credit loss impairment model (“CECL”), which requires consideration of a broader range of reasonable and supportable information to estimate expected credit losses over the life of the instrument instead of only when losses are incurred. This standard applies to financial assets measured at amortized cost basis and net investments in leases recognized by the lessor. Upon adoption, a cumulative effect adjustment of $2,293,000 was made to deficit as part of the modified retrospective transition approach. Simplifying test for goodwill impairment Effective January 1, 2020, the Company adopted ASU 2017-04, “Simplifying the Test for Goodwill Impairment.” ASU 2017-04 eliminates the need to determine the fair value of individual assets and liabilities of a reporting unit to measure the implied goodwill impairment. As a result of the adoption, the Company now calculates goodwill impairment as the amount by which the carrying value exceeds fair value of a reporting unit, not to exceed the carrying amount of goodwill. (v) Discontinuation of LIBOR In March 2020, FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848)”, which provides optional relief for the discontinuation of LIBOR resulting from rate reform. Contract terms that are modified due to the replacement of a reference rate are not required to be remeasured or reassessed under FASB’s relevant U.S. GAAP Topic. The election is available by Topic. This guidance is effective for all entities as of March 12, 2020 through December 31, 2022 and may be applied from the beginning of an interim period that includes the issuance date of the ASU. The Company is currently evaluating the impact this guidance. 2. Significant accounting policies (continued): (w) Recent accounting pronouncements Debt with conversion and other options In August 2020, FASB issued ASU 2020-06, “Debt – Debt with Conversion and Other Options (Subtopic 470-20)”, which simplifies the accounting for convertible debt instruments by reducing the number of accounting models and circumstances when embedded conversion features are separately recognized. This update also revises the method in which diluted EPS is calculated related to certain instruments with conversion features, among other clarifications. The guidance is effective for annual reporting periods beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company is currently evaluating the impact of this guidance.

Significant accounting polici_3

Significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Useful Lives Used for Calculating Depreciation and Amortization	A summary of the useful lives used for calculating depreciation and amortization is as follows: Turbines 25 years Generators 15 years Transformers 15 years
Schedule of Recently Adopted Accounting Pronouncements	The impacts of the adoption of ASU 2016-02 are as follows: (in millions of US dollars) As reported at December 31, 2018 Adjustments Adjusted at January 1, 2019 Right-of-use assets (1) (2) $ — $ 1,068.3 $ 1,068.3 Other assets (2) 204.9 (17.3 ) 187.6 Accounts payable and accrued liabilities (1) 70.2 (2.5 ) 67.7 Current portion of operating lease liabilities (1) — 160.2 160.2 Current portion of other long-term liabilities (3) 32.2 (22.2 ) 10.0 Operating lease liabilities (1) — 893.3 893.3 Other long-term liabilities (3) 181.1 (158.9 ) 22.2 Deficit (3) (645.6 ) 181.1 (464.5 ) (1) Upon adoption of ASU 2016-02, the Company recorded non-cash right-of-use assets and operating lease liabilities on the balance sheet for its vessel sale-leaseback transactions and office leases under operating lease arrangements. Prior to January 1, 2019, operating leases were not included on the balance sheet and were recorded as operating lease expenses when incurred. The amount recognized as operating lease liabilities was based on the present value of future minimum lease payments, discounted using the lessor’s rate implicit in the lease or the Company’s incremental borrowing rate if the lessor’s implicit rate is not readily determinable and includes any existing accrued payments related to lease liabilities. Minimum lease payments referenced to an indexed rate were determined based on the respective rates at the adoption date. (2) Initial direct costs related to the Company’s vessel sale-leaseback transactions under operating lease arrangements were reclassified from other assets to right-of-use assets. (3) Deferred gain related to the Company’s vessel sale-leaseback transactions was recognized through deficit on the initial date of application.

Acquisition of Apple Bidco Li_2

Acquisition of Apple Bidco Limited (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of Net Purchase Price	The net purchase price of $287,700,000 comprises of the following. Adjustments have been made from what was originally reported as a result of settlement of purchase price adjustments: As originally reported Adjustments As adjusted 29,891,266 common shares issued (1) $ 316.8 — $ 316.8 6,664,270 Holdback Shares (1) 70.6 — 70.6 Less: Contingent consideration asset (2) (41.5 ) (53.7 ) (95.2 ) Less: Purchase price adjustment (3) (52.5 ) 48.0 (4.5 ) Net purchase price $ 293.4 $ (5.7 ) $ 287.7 (1) (2) (3)
Summary of Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date. Adjustments have been made from what was previously reported as a result of settlement of purchase price adjustments and refinements of estimates. As originally reported Adjustments As adjusted Cash and cash equivalents $ 36.7 — $ 36.7 Inventory 54.4 (13.5 ) 40.9 Acquisition related assets (1) 65.0 31.4 96.4 Accounts receivable (2) 41.4 7.7 49.1 Other current assets 7.9 1.2 9.1 Property, plant and equipment 597.3 (150.1 ) 447.2 Intangible assets 35.4 (8.0 ) 27.4 Deferred tax assets 23.5 (6.9 ) 16.6 Other assets 13.9 — 13.9 Goodwill — 117.9 117.9 Total assets acquired 875.5 (20.3 ) 855.2 Accounts payable and accrued liabilities 91.3 1.2 92.5 Income tax payable 104.0 2.5 106.5 Other current liabilities 17.2 — 17.2 Long-term debt (including current and non-current portions) (3) 311.6 — 311.6 Deferred tax liabilities 7.0 (6.0 ) 1.0 Other long-term liabilities 51.0 (12.3 ) 38.7 Net assets acquired $ 293.4 $ (5.7 ) $ 287.7 (1) (2) (3)
Summary of Pro forma Financial Information	The following table presents unaudited pro forma results for the year ended December 31, 2020 and 2019. The unaudited pro forma financial information combines the results of operations of the Company and APR Energy as though the acquisition had occurred as of January 1, 2019. The pro forma results contain adjustments that are directly attributable to the transaction, including depreciation of the fair value of property, plant and equipment, amortization of acquired intangible assets, and refinancing of debt. Additionally, pro forma net earnings were adjusted to exclude acquisition-related costs incurred. Year ended December 31, Pro forma information 2020 2019 Revenue $ 1,464.6 $ 1,452.9 Net earnings 179.3 454.4

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Financial Information by Segment	Year ended December 31, 2020 Containership Leasing Mobile Power Generation Elimination and Other Total Revenue $ 1,222.8 $ 198.3 $ — $ 1,421.1 Operating expense 243.4 31.4 — 274.8 Depreciation and amortization expense 288.1 65.8 — 353.9 General and administrative expense 36.6 36.9 (8.1 ) 65.4 Operating leases 147.3 3.2 — 150.5 Goodwill impairment — 117.9 — 117.9 Interest expense 176.0 19.5 (3.9 ) 191.6 Interest income (1.4 ) (3.6 ) — (5.0 ) Income tax expense 1.0 15.6 — 16.6 Year ended December 31, 2020 Containership leasing adjusted EBITDA $ 795.5 Mobile power generation adjusted EBITDA 127.0 Total segment adjusted EBITDA 922.5 Eliminations and other (1.3 ) Depreciation and amortization 353.9 Interest expense 191.6 Interest income (5.0 ) Loss on derivative instruments 35.5 Other expenses 8.6 Gain on contingent consideration asset (6.8 ) Loss on foreign currency repatriation 18.7 Loss on sale 0.2 Goodwill impairment 117.9 Consolidated net earnings before taxes $ 209.2 December 31, 2020 Containership Leasing Mobile Power Generation Elimination and Other Total Total assets $ 8,475.4 $ 829.9 $ (16.2 ) $ 9,289.1 Capital expenditures by segment: Year ended December 31, 2020 Containership leasing $ 848.1 Mobile power generation 17.6

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Summary of Revenue Disaggregated by Segment and by Type	Revenue disaggregated by segment and by type for the year ended December 31, 2020 is as follows: Containership Leasing (1) Mobile Power Generation Total Operating lease revenue $ 1,180.0 $ 187.4 $ 1,367.4 Interest income from leasing 40.5 — 40.5 Other 2.3 10.9 13.2 $ 1,222.8 $ 198.3 $ 1,421.1 (1) 2019 2018 Operating lease revenue $ 1,096.0 $ 1,061.1 Interest income from leasing 35.5 35.2 $ 1,131.5 $ 1,096.3
Schedule of Future Minimum Revenues Committed	As at December 31, 2020, the minimum future revenues to be received on committed operating leases, interest income to be earned from direct financing leases and other revenue are as follows: Operating lease revenue (1) Direct financing leases (2) Other Total committed revenue 2021 $ 1,354.1 $ 36.1 $ 10.0 $ 1,400.2 2022 1,051.1 34.4 4.1 1,089.6 2023 722.9 32.5 0.7 756.1 2024 447.9 30.3 — 478.2 2025 264.6 28.2 — 292.8 Thereafter 274.6 180.7 — 455.3 $ 4,115.2 $ 342.2 $ 14.8 $ 4,472.2 (1) (2)
Schedule of Future Minimum Revenues Received Based on Segment	As at December 31, 2020, the minimum future revenues to be received based on each segment are as follows: Containership Leasing (1) (2) Mobile Power Generation Total committed revenue 2021 $ 1,243.1 $ 157.1 $ 1,400.2 2022 1,000.9 88.7 1,089.6 2023 718.0 38.1 756.1 2024 478.2 — 478.2 2025 292.8 — 292.8 Thereafter 455.3 — 455.3 $ 4,188.3 $ 283.9 $ 4,472.2 (1) (2)
Schedule of Revenue Derived from Customers	The Company’s revenue is derived from the following customers: 2020 2019 2018 COSCO $ 401.1 $ 407.4 $ 412.3 Yang Ming Marine 255.7 257.5 235.6 ONE 237.3 199.4 241.6 Other 527.0 267.2 206.8 $ 1,421.1 $ 1,131.5 $ 1,096.3

Net investment in lease (Tables

Net investment in lease (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Net Investment In Lease	2020 2019 Undiscounted lease receivable $ 773.2 $ 1,224.2 Unearned interest income (343.9 ) (465.4 ) Net investment in lease $ 429.3 $ 758.8 2020 2019 Lease receivables $ 429.3 $ 608.8 Unguaranteed residual value - 150.0 Net investment in lease 429.3 758.8 Current portion of net investment in lease (10.7 ) (35.2 ) Long-term portion of net investment in lease $ 418.6 $ 723.6
Schedule of Minimum Lease Receivable from Direct Financing Leases	At December 31, 2020, the minimum lease receivable from direct financing leases are as follows: 2021 $ 44.3 2022 44.3 2023 44.3 2024 44.5 2025 44.4 Thereafter 551.4 $ 773.2

Property, plant and equipment (

Property, plant and equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property, Plant and Equipment	Accumulated Net book December 31, 2020 Cost depreciation value Vessels $ 9,148.9 $ (2,571.3 ) $ 6,577.6 Equipment and other 543.1 (146.0 ) 397.1 Property, plant and equipment $ 9,692.0 $ (2,717.3 ) $ 6,974.7 Accumulated Net book December 31, 2019 Cost depreciation value Vessels $ 8,018.5 $ (2,311.4 ) $ 5,707.1 Equipment and other 4.6 (4.0 ) 0.6 Property, plant and equipment $ 8,023.1 $ (2,315.4 ) $ 5,707.7

Right-of-use assets (Tables)

Right-of-use assets (Tables)	12 Months Ended
	Dec. 31, 2020
Operating Lease Right Of Use Assets [Abstract]
Schedule of Right-of-Use Assets	December 31, 2019 Cost Accumulated amortization Net book value Vessel operating leases $ 1,060.9 $ (110.1 ) $ 950.8 Office operating leases 8.2 (1.8 ) 6.4 Right-of-use assets $ 1,069.1 $ (111.9 ) $ 957.2

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Containership leasing Mobile power generation Balance, December 31, 2019 $ 75.3 $ — Goodwill arising from acquisition of APR Energy (note 3) — 117.9 Impairment loss recognized during the period — (117.9 ) Balance, December 31, 2020 $ 75.3 $ —

Other assets (Tables)

Other assets (Tables)	12 Months Ended
	Dec. 31, 2020
Other Assets [Abstract]
Schedule of Other Assets	2020 2019 Intangible assets (a) $ 104.8 $ 94.0 Deferred dry-dock (b) 63.8 41.3 Restricted cash (c) 38.2 — Contingent consideration asset (d) 84.0 — Vessels under construction (e) 42.0 — Other 42.9 37.2 Other assets $ 375.7 $ 172.5 (a) Intangible assets: December 31, 2020 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (58.6 ) $ 71.3 Trademark 27.4 (1.1 ) 26.3 Other 11.5 (4.3 ) 7.2 $ 168.8 $ (64.0 ) $ 104.8 December 31, 2019 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (39.3 ) $ 90.6 Other 6.6 (3.2 ) 3.4 $ 136.5 $ (42.5 ) $ 94.0 As part of the acquisition of APR Energy on February 28, 2020, the Company recorded $27,400,000 related to the fair value of a trademark. The trademark is amortized on a straight-line basis over its estimated useful life of 20 years. Acquired customer contracts are amortized on a straight-line basis over their remaining useful lives. As of December 31, 2020, the weighted average remaining useful lives of acquired customer contracts was 5 years (2019 – 5 years). During the year ended December 31, 2020, the Company recorded $21,396,000 of amortization related to intangible assets (2019 – $20,729,000, 2018 – $16,569,000). Future amortization of intangible assets is as follows: 2021 $ 19.1 2022 18.2 2023 14.5 2024 11.7 2025 8.3 Thereafter 33.0 $ 104.8 11 . Other assets (continued): (b) Deferred dry-dock: During the year ended December 31, 2020, changes in deferred dry-dock were as follows: December 31, 2018 36.7 Costs incurred 23.5 Amortization expensed (1) (18.9 ) December 31, 2019 41.3 Costs incurred 45.2 Amortization expensed (1) (22.7 ) December 31, 2020 $ 63.8 (1) Amortization of dry-docking costs is included in depreciation and amortization (c) Restricted cash: Restricted cash consists primarily of amounts held in reserve accounts related to the Company’s debt facilities. (d) Contingent consideration asset: As a part of the acquisition of APR Energy on February 28, 2020, the Company is compensated by the Sellers for certain losses that may be incurred on future cash repatriation from a foreign jurisdiction until the earlier of (1) reaching the maximum cash flows subject to compensation, (2) termination of specified contracts, (3) sustaining the ability to repatriate cash without losses and (4) April 30, 2022. The amount of compensation depends on the Company’s ability to generate cash flows on specific contracts in the foreign jurisdiction and the magnitude of losses incurred on repatriation. The maximum amount of cash flows subject to compensation is $110,000,000. Fairfax agreed, subject to definitive documentation, to compensate the Company for future losses realized on sale or disposal of certain property, plant and equipment and inventory items calculated as the difference between the proceeds on sale or disposal and the book value of the respective assets at February 28, 2020, prior to acquisition. The maximum amount of losses subject to compensation is $64,000,000. Contingent consideration asset, December 31, 2019 $ — Assets acquired 95.2 Change in fair value 6.8 Compensation received (11.1 ) Contingent consideration asset 90.9 Current portion included in prepaid expenses and other (6.9 ) Contingent consideration asset, December 31, 2020 $ 84.0 (e) Vessels under construction: Vessels under construction include installment payments, interest and financing costs incurred on the construction of new vessels, net of address commissions. In November 2020, the Company entered into agreements with a shipyard to build five 12200 TEU vessels for an aggregate purchase price of $419,825,000, net of address commissions, payable in four installments (note 21(b)). As of December 31, 2020, $41,982,500, net of address commissions, relating to the first installment was paid.

Long-term debt (Tables)

Long-term debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	2020 2019 Long-term debt: Revolving credit facilities (a) (c) $ 772.1 $ 867.0 Term loan credit facilities (b) (c) 2,094.7 1,799.4 Senior unsecured notes (d) 80.0 80.0 Fairfax Notes (e) 600.0 500.0 Exchangeable Notes (f) 201.3 — 3,748.1 3,246.4 Fair value adjustment on term loan credit facilities (0.1 ) (0.1 ) Debt discount on Fairfax Notes ( e ) (130.9 ) (150.9 ) Debt discount on Exchangeable Notes (f) (6.1 ) — Deferred financing fees (44.9 ) (34.8 ) Long-term debt 3,566.1 3,060.6 Current portion of long-term debt (332.1 ) (363.7 ) Long-term debt $ 3,234.0 $ 2,696.9
Schedule of Future Minimum Repayments Under Revolving Credit Facilities and Term Loans	The following is a schedule of future minimum repayments under the Company’s term loan credit facilities as of December 31, 2020: 2021 $ 286.1 2022 187.9 2023 364.5 2024 877.2 2025 222.7 Thereafter 156.3 $ 2,094.7

Operating Lease Liabilities (Ta

Operating Lease Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Operating Lease Liabilities	December 31, December 31, 2020 2019 Operating lease commitments $ 927.0 $ 1,107.6 Impact of discounting (141.5 ) (184.4 ) Impact of changes in variable rates 44.7 19.1 Operating lease liabilities 830.2 942.3 Current portion of operating lease liabilities (160.9 ) (159.7 ) Operating lease liabilities $ 669.3 $ 782.6
Schedule of Operating Lease Costs Related To Vessel Sale-leaseback Transactions And Other Leases	Operating lease costs related to vessel sale-leaseback transactions and other leases are summarized as follows: Year ended December 31, 2020 Year ended December 31, 2019 Lease costs: Operating lease costs $ 166.5 $ 160.0 Variable lease adjustments (12.4 ) (3.0 ) Other information: Operating cash outflow used for operating leases 147.8 153.2 Weighted average discount rate 4.8 % 4.8 % Weighted average remaining lease term 7 years 8 years

Other Financing Arrangements (T

Other Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Other Financing Arrangements	2020 2019 Other financing arrangements $ 879.5 $ 513.8 Deferred financing fees (13.7 ) (5.3 ) Other financing arrangements 865.8 508.5 Current portion of other financing arrangements (64.1 ) (134.6 ) Other financing arrangements $ 801.7 $ 373.9
Schedule of Repayments Due for Other Financing Arrangements	Based on amounts funded for other financing arrangements, payments due to lessors would be as follows: 2021 $ 64.6 2022 64.6 2023 64.6 2024 64.6 2025 57.4 Thereafter 563.7 $ 879.5

Other liabilities (Tables)

Other liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Other Long Term Liabilities [Line Items]
Schedule of Other Long-Term Liabilities	2020 2019 Asset retirement obligations (a) $ 42.3 $ — Other 23.4 19.0 Other long-term liabilities 65.7 19.0 Current portion of other long-term liabilities (24.8 ) (7.8 ) Other long-term liabilities $ 40.9 $ 11.2 ( a) Asset retirement obligations:
APR Energy [Member]
Other Long Term Liabilities [Line Items]
Schedule of Change in Asset Retirement Obligation	Asset retirement obligations were assumed as part of the APR Energy acquisition and consist of the contractual requirement to demobilize the Company’s mobile power generation sites when there is a legal obligation associated with the demobilization and the fair value of the liability can be reasonably estimated. Asset retirement obligations, December 31, 2019 $ — Liabilities acquired 45.9 Liabilities incurred 5.3 Liabilities settled (6.6 ) Provision reassessment (2.9 ) Accretion expense 0.6 Asset retirement obligations, December 31, 2020 $ 42.3

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Net earnings before income taxes for the year ended December 31, 2020 relates only to the foreign jurisdictions. Similarly, the Company’s income tax expense for the year ended December 31, 2020 related only to foreign jurisdictions and consists of the following: 2020 Current tax Domestic Foreign Total Current tax expense $ — $ 20.2 $ 20.2 $ — $ 20.2 $ 20.2 Deferred tax Deferred tax expense $ — $ (3.6 ) $ (3.6 ) $ — $ (3.6 ) $ (3.6 ) Total tax expense $ — $ 16.6 $ 16.6
Reconciliation between Effective Tax Rate	For the year ended December 31, 2020, the reconciliation between the effective tax rate of 7.94% and the statutory UK income tax rate of 19.0% 2020 Computed "Expected" tax expense: Computed tax expense on income from continuing operations $ 39.7 Increase (reduction) in income taxes resulting from: Certain income from containership leasing segment that is exempt from tax (58.0 ) Goodwill impairment not deductible for tax 22.4 Change in valuation allowance 25.4 Change in current year uncertain tax positions 1.2 Change in tax law (0.1 ) Foreign rate differential (26.8 ) Withholding taxes 7.8 Other, net 5.0 $ 16.6
Schedule of Deferred Tax Assets and Liabilities	The deferred tax assets and liabilities were as follows for the year ended 31 December, 2020: Deferred tax assets 2020 Decommission provisions 16.6 Property, plant and equipment 25.9 Reserves and accrued expenses 63.9 Tax losses carried forward 40.4 Interest allowance 16.8 Deferred revenue 0.4 Valuation allowance (129.3 ) $ 34.7 Deferred tax liabilities 2020 Deferred job costs (3.8 ) Accelerated asset costs (2.7 ) Inflation adjustment (5.2 ) Other timing differences (3.7 ) $ (15.4 ) Net deferred tax asset $ 19.3
Summary of Unrecognized Tax Benefits	The following table summarizes the activity related to the Company’s unrecognized tax benefits: 2020 Balance as of December 31, 2019 - Acquired as part of APR Energy acquisition (note 3) 75.4 Decreases due to tax provisions expired 1.2 Balance as of December 31, 2020 $ 76.6

Preferred shares and share ca_2

Preferred shares and share capital (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of Preferred Shares Outstanding	As at December 31, 2020, the Company had the following preferred shares outstanding: Liquidation preference Shares Dividend rate Redemption by Company December December Series Authorized Issued per annum permitted on or after 2020 2019 D 20,000,000 5,093,728 7.95 % January 30, 2018 (1) 127.3 127.3 E 15,000,000 5,415,937 8.25 % February 13, 2019 (1) 135.4 135.4 G 15,000,000 7,800,800 8.20 % June 16, 2021 (1) 195.0 195.0 H 15,000,000 9,025,105 7.875 % August 11, 2021 (1) 225.6 225.6 I 6,000,000 6,000,000 8.00 % October 30, 2023 (1) 150.0 150.0 (1) Redeemable by the Company, in whole or in part, at a redemption price of $25.00 per share plus unpaid dividends. The preferred shares are not convertible into common shares and are not redeemable by the holder .

Earnings per share (_EPS_) (Tab

Earnings per share (“EPS”) (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Reconciliation of Numerator and Denominator Used in Basic and Diluted EPS Computations	Year ended December 31, 2020 For the year ended December 31, 2020 Earnings (numerator) Shares (denominator) Per share amount Net earnings 192.6 Less preferred share dividends: Series D (10.1 ) Series E (11.2 ) Series G (16.0 ) Series H (17.8 ) Series I (12.0 ) Basic EPS: Net earnings attributable to common shareholders $ 125.5 241,502,000 $ 0.52 Effect of dilutive securities: Share-based compensation — 541,000 Fairfax warrants — 3,096,000 Holdback shares — 5,375,000 Diluted EPS (1) Net earnings attributable to common shareholders $ 125.5 250,514,000 $ 0.50 (1) The Exchangeable Notes are not included in the computation of diluted EPS when their effects are anti-dilutive. Year ended December 31, 2019 For the year ended December 31, 2019 Earnings (numerator) Shares (denominator) Per share amount Net earnings $ 439.1 Less preferred share dividends: Series D (14.1 ) Series E (11.2 ) Series G (16.0 ) Series H (17.8 ) Series I (12.0 ) Basic EPS: Net earnings attributable to common shareholders $ 368.0 214,499,000 $ 1.72 Effect of dilutive securities: Share-based compensation — 471,000 Fairfax warrants — 4,902,000 Diluted EPS: Net earnings attributable to common shareholders $ 368.0 219,872,000 $ 1.67 18. Earnings per share (“EPS”) (continued): Year ended December 31, 2018 For the year ended December 31, 2018 Earnings (numerator) Shares (denominator) Per share amount Net earnings $ 278.8 Less preferred share dividends: Series D (14.6 ) Series E (11.2 ) Series F (8.3 ) Series G (16.0 ) Series H (17.8 ) Series I (3.4 ) Basic EPS: Net earnings attributable to common shareholders $ 207.5 154,848,000 $ 1.34 Effect of dilutive securities: Share-based compensation — 91,000 Fairfax warrants — 3,129,000 Diluted EPS (1) Net earnings attributable to common shareholders $ 207.5 158,068,000 $ 1.31 (1) The convertible Series F preferred shares are not included in the computation of diluted EPS when their effects are anti-dilutive.

Share-based compensation (Table

Share-based compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Outstanding Restricted Shares, Phantom Share Units, SARs and Restricted Stock Units	A summary of the Company’s outstanding restricted shares, phantom share units, stock appreciation rights (“SARs”) and restricted stock units as of and for the twelve months ended December 31, 2020, 2019, and 2018 are presented below: Restricted shares Phantom share units SARs Restricted stock units Stock options Number W.A. Number W.A. grant Number of W.A. grant Number W.A. grant Number W.A. grant of shares date FV of units date FV SARs date FV of units date FV of options date FV December 31, 2017 94,533 8.89 727,001 13.60 485,974 3.40 71,184 7.80 — — Granted 164,326 7.19 30,000 6.86 — — 609,248 8.18 500,000 2.45 Vested and exercised (119,509 ) 8.52 (113,333 ) 18.80 — — (83,220 ) 9.87 — — Expired — — — — (485,974 ) 3.40 — — — — Cancelled (53,608 ) 7.10 (76,666 ) 7.90 — — (12,441 ) 7.28 — — December 31, 2018 85,742 $ 7.28 567,002 $ 12.97 — $ — 584,771 $ 7.91 500,000 $ 2.45 Granted 67,400 8.15 — — — — 249,732 8.90 — — Vested and exercised (85,742 ) 7.28 (60,001 ) 16.68 — — (224,073 ) 8.59 — — Cancelled — — — — — — (33,466 ) 9.05 — — December 31, 2019 67,400 $ 8.15 507,001 $ 12.53 — $ — 576,964 $ 8.01 500,000 $ 2.45 Granted 1,051,492 7.84 — — — — 1,824,786 7.83 1,500,000 2.57 Vested and exercised (67,400 ) 8.15 (20,000 ) 6.85 — — (313,231 ) 9.32 — — Cancelled — — — — — — (79,635 ) 9.84 — — December 31, 2020 1,051,492 $ 7.84 487,001 $ 12.76 — $ — 2,008,884 $ 7.57 2,000,000 $ 2.51 Vested and exercisable, December 31, 2020 — $ — 487,001 $ 12.76 — $ — — $ — 200,000 $ 2.54

Other Information (Tables)

Other Information (Tables) - Seaspan [Member]	12 Months Ended
	Dec. 31, 2020
Other Information [Line Items]
Schedule of Accounts Payable and Accrued Liabilities	(a) Accounts payable and accrued liabilities: The principal components of accounts payable and accrued liabilities are: 2020 2019 Accrued interest $ 17.2 $ 17.1 Accounts payable and other accrued liabilities 116.9 66.3 $ 134.1 $ 83.4
Schedule of Supplemental Cash Flow Information	(b) Supplemental cash flow information: 2020 2019 2018 Interest paid $ 156.2 $ 183.1 $ 194.3 Interest received 5.0 8.9 3.7 Undrawn credit facility fee paid 0.8 1.7 0.6 Income taxes paid 16.8 — — Non-cash investing and financing transactions: Dividend reinvestment 0.3 1.2 22.8 Arrangement and transaction fee settled in shares — — 2.3 Commencement of sales-type lease 57.0 316.7 — Carrying value of previously held equity in GCI settled on acquisition — — 61.9 Issuance of common shares on GCI acquisition — — 13.9 Issuance of warrants — — 67.5 Issuance of Series D preferred shares on GCI acquisition — — 47.2 Settlement of GCI transaction fees paid by the Company — — 15.2 Settlement of loans to affiliate, accrued interest and other intercompany balances on GCI acquisition — — 38.8 APR Energy loans settled in shares 8.3 — — Common shares issued on APR Energy acquisition 316.8 — — Holdback Shares reserved on APR Energy acquisition 70.6 — — Purchase price adjustment related to APR Energy acquisition 4.5 — — Reclassification on lease modification 377.4 — — Contingent consideration asset related to APR Energy acquisition 95.2 — — Net assets acquired on APR Energy acquisition 287.7 — — ARO liabilities incurred 5.3 — — ARO provision re-assessment 2.9 — — Refinancing of existing term loan credit facilities with draws made on new debt — 302.7 — Right-of-use assets arising from new operating leases 1.2 0.7 — Cancellation of common shares issued on APR Energy acquisition 12.5 — — Prepayments transferred to property, plant and equipment upon vessel delivery 46.8 — — Changes in operating assets and liabilities Accounts receivable (17.1 ) (2.3 ) 15.5 Inventories (5.9 ) 6.3 0.5 Prepaids expenses and other (10.3 ) (0.9 ) 17.0 Net investment in lease 13.3 9.3 44.3 Accounts payable and accrued liabilities (16.4 ) 11.5 (7.0 ) Settlement of decommissioning provisions (5.9 ) — — Deferred revenue 8.4 (0.6 ) (46.8 ) Income tax payable 3.9 — — Major maintenance (54.6 ) (22.3 ) (10.3 ) Other liabilities (8.6 ) — (1.5 ) Operating lease liabilities (114.7 ) (111.9 ) — Derivative instruments 22.5 55.0 42.0 Contingent consideration asset 18.7 — —
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the amounts shown in the consolidated statements of cash flows: 2020 2019 2018 Cash and cash equivalents $ 304.3 $ 195.0 $ 357.3 Restricted cash included in prepaid and other — 2.3 — Restricted cash included in other assets (note 11) 38.2 — 14.1 Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows $ 342.5 $ 197.3 $ 371.4

Commitments and contingencies (

Commitments and contingencies (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Schedule of Commitment Under Operating Leases	At December 31, 2020, the commitment under operating leases for vessels is $917,130,000 for 2021 to 2029 and for other leases is $9,893,000 for 2021 to 2024. Total commitments under these leases are as follows: 2021 $ 147.1 2022 143.1 2023 144.6 2024 147.8 2025 125.7 Thereafter 218.7 $ 927.0
Summary of Outstanding Commitments for Remaining Installment Payments	The Company has outstanding commitments for the remaining installment payments as follows: 2021 $ 142.7 2022 235.1 Total $ 377.8

Financial instruments (Tables)

Financial instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Financial Instruments [Abstract]
Schedule of Outstanding Interest Rate Derivatives	As of December 31, 2020, the Company had the following outstanding interest rate derivatives: Fixed per annum rate swapped for LIBOR Notional amount as of December 31, 2020 Maximum notional amount (1) Effective date Ending date 5.4200% $ 302.3 $ 302.3 September 6, 2007 May 31, 2024 1.6490% 160.0 160.0 September 27, 2019 May 14, 2024 0.7270% 125.0 125.0 March 26, 2020 March 26, 2025 0.7800% 125.0 125.0 March 23, 2020 March 23, 2025 1.6850% 110.0 110.0 November 14, 2019 May 15, 2024 5.6000% 93.6 93.6 June 23, 2010 December 23, 2021 (2) 1.4900% 29.4 29.4 February 4, 2020 December 30, 2025 (1) Over the term of the interest rate swaps, the notional amounts increase and decrease. These amounts represent the peak notional amount over the remaining term of the swap. (2) Prospectively de-designated as an accounting hedge in 2008.
Summary of Financial Instruments Measured at Fair Value	The following provides information about the Company’s financial instruments measured at fair value: 2020 2019 Contingent consideration asset $ 90.9 $ — Fair value of derivative liabilities Interest rate swaps 63.0 49.3 Derivative put instrument — 0.9
Schedule of Gains and Losses Reclassified from Accumulated Other Comprehensive Loss into Earnings	The following table provides information about gains and losses included in net earnings and reclassified from accumulated other comprehensive loss (“AOCL”) into earnings: 2020 2019 2018 Earnings (losses) recognized in net earnings: Loss on interest rate swaps (1) $ (36.4 ) $ (58.8 ) $ 14.7 Gain on derivative put instrument 0.9 23.7 0.8 Gain on contingent consideration asset 6.8 — — Loss reclassified from AOCL to net earnings (2) Interest expense (0.3 ) (0.3 ) (0.3 ) Depreciation and amortization (1.0 ) (0.7 ) (0.8 ) (1) For the years ended December 31, 2020, 2019 and 2018, cash flows related to actual settlement of interest rate swaps were $21,789,000, $126,782,000 and $41,284,000 respectively. These are included in investing activities on the consolidated statements of cash flows. For the years ended December 31, 2018, cash flows related to actual settlement of interest rate swaps of $41,284,000 was reclassified from operating activities to investing activities to conform with current financial statement presentation. (2) The effective portion of changes in unrealized loss on interest rate swaps was recorded in accumulated other comprehensive loss until September 30, 2008 when these contracts were voluntarily de-designated as accounting hedges. The amounts in accumulated other comprehensive loss are recognized in earnings when and where the previously hedged interest is recognized in earnings.

General - Additional Informatio

General - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020	Feb. 28, 2020
Summary Of Significant Accounting Policies [Line Items]
Company incorporation date	Oct. 1, 2019
APR Energy Ltd [Member] | Apple Bidco [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment ownership percentage		100.00%

Significant accounting polici_4

Significant accounting policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2020
Summary Of Significant Accounting Policies [Line Items]
Lessee, operating lease, lease term	12 months
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Credit loss on financial instruments		$ 2,293,000
Vessels [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life	30 years
Number of years between dry-docking	5 years

Significant accounting polici_5

Significant accounting policies - Summary of Useful Lives Used for Calculating Depreciation and Amortization (Detail)	12 Months Ended
	Dec. 31, 2020
Turbines [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment, useful life	25 years
Generators [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment, useful life	15 years
Transformers [Member]
Property Plant And Equipment [Line Items]
Property plant and equipment, useful life	15 years

Significant accounting polici_6

Significant accounting policies - Impact of Adoption of ASU 2016-02 (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Right-of-use assets	$ 841,200,000	$ 957,200,000	$ 1,068,300,000	$ 0
Other assets	375,700,000	172,500,000	187,600,000	204,900,000
Accounts payable and accrued liabilities	134,100,000	83,400,000	67,700,000	70,200,000
Current portion of operating lease liabilities	160,900,000	159,700,000	160,200,000	0
Current portion of other long-term liabilities	24,800,000	7,800,000	10,000,000	32,200,000
Operating lease liabilities	830,200,000	942,308,000	893,300,000	0
Other long-term liabilities	40,900,000	11,200,000	22,200,000	181,100,000
Deficit	$ (199,200,000)	$ (200,700,000)	(464,500,000)	$ (645,600,000)
Accounting Standards Update 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Right-of-use assets			1,068,300,000
Other assets			(17,300,000)
Accounts payable and accrued liabilities			(2,500,000)
Current portion of operating lease liabilities			160,200,000
Current portion of other long-term liabilities			(22,200,000)
Operating lease liabilities			893,300,000
Other long-term liabilities			(158,900,000)
Deficit			$ 181,100,000

Acquisition of Apple Bidco Li_3

Acquisition of Apple Bidco Limited - Additional Information (Detail) - USD ($)	Feb. 28, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Revenue				$ 1,421,100,000	$ 1,131,500,000	$ 1,096,300,000
Net loss				(192,600,000)	(439,100,000)	$ (278,800,000)
Goodwill		$ 75,300,000	$ 75,300,000	75,300,000	$ 75,300,000
APR Energy [Member]
Business Acquisition [Line Items]
Shares issued	29,891,266
Shares reserved for future issuance	6,664,270
Net purchase price	$ 287,700,000
Goodwill	$ 117,900,000
APR Energy [Member] | General and Administrative Expense [Member]
Business Acquisition [Line Items]
Acquisition related costs		$ 2,294,000		$ 1,498,000
APR Energy [Member]
Business Acquisition [Line Items]
Business acquisition date	Feb. 28, 2020
Revenue			198,300,000
Net loss			$ 4,000,000
APR Energy [Member] | Fairfax Financial Holdings Limited [Member]
Business Acquisition [Line Items]
Equity method investment ownership percentage	100.00%
Acquired percentage	67.80%

Acquisition of Apple Bidco Li_4

Acquisition of Apple Bidco Limited - Schedule of Net Purchase Price (Detail) - APR Energy [Member]	Feb. 28, 2020USD ($)
Business Acquisition [Line Items]
Common shares issued	$ 316,800,000
Holdback Shares	70,600,000
Less: Contingent consideration asset	(95,200,000)
Less: Purchase price adjustment	(4,500,000)
Net purchase price	287,700,000
As Originally Reported [Member]
Business Acquisition [Line Items]
Common shares issued	316,800,000
Holdback Shares	70,600,000
Less: Contingent consideration asset	(41,500,000)
Less: Purchase price adjustment	(52,500,000)
Net purchase price	293,400,000
Adjustments [Member]
Business Acquisition [Line Items]
Common shares issued	0
Holdback Shares	0
Less: Contingent consideration asset	(53,700,000)
Less: Purchase price adjustment	48,000,000
Net purchase price	$ (5,700,000)

Acquisition of Apple Bidco Li_5

Acquisition of Apple Bidco Limited - Schedule of Net Purchase Price (Parenthetical) (Detail) - $ / shares	Feb. 28, 2020	Dec. 31, 2020
Fairfax Financial Holdings Limited [Member]
Business Acquisition [Line Items]
Warrants outstanding term		5 years
Warrants to purchase common shares		5,000,000
Warrants outstanding exercise price		$ 13
APR Energy [Member]
Business Acquisition [Line Items]
Shares issued	29,891,266
Shares reserved for future issuance	6,664,270
Shares forfeited		577,139
Common shares previously issued		1,849,641
Shares permanently forfeited for post closing purchase price adjustments		1,122,290
Treasury shares		727,351
Common shares released from holdback		318,637

Acquisition of Apple Bidco Li_6

Acquisition of Apple Bidco Limited - Summary of Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($)	Dec. 31, 2020	Feb. 28, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 75,300,000		$ 75,300,000
APR Energy [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		$ 36,700,000
Inventory		40,900,000
Acquisition related assets		96,400,000
Accounts receivable		49,100,000
Other current assets		9,100,000
Property, plant and equipment		447,200,000
Intangible assets		27,400,000
Deferred tax assets		16,600,000
Other assets		13,900,000
Goodwill		117,900,000
Total assets acquired		855,200,000
Accounts payable and accrued liabilities		92,500,000
Income tax payable		106,500,000
Other current liabilities		17,200,000
Long-term debt (including current and non-current portions)		311,600,000
Deferred tax liabilities		1,000,000
Other long-term liabilities		38,700,000
Net assets acquired		287,700,000
As Originally Reported [Member] | APR Energy [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		36,700,000
Inventory		54,400,000
Acquisition related assets		65,000,000
Accounts receivable		41,400,000
Other current assets		7,900,000
Property, plant and equipment		597,300,000
Intangible assets		35,400,000
Deferred tax assets		23,500,000
Other assets		13,900,000
Goodwill		0
Total assets acquired		875,500,000
Accounts payable and accrued liabilities		91,300,000
Income tax payable		104,000,000
Other current liabilities		17,200,000
Long-term debt (including current and non-current portions)		311,600,000
Deferred tax liabilities		7,000,000
Other long-term liabilities		51,000,000
Net assets acquired		293,400,000
Adjustments [Member] | APR Energy [Member]
Business Acquisition [Line Items]
Cash and cash equivalents		0
Inventory		(13,500,000)
Acquisition related assets		31,400,000
Accounts receivable		7,700,000
Other current assets		1,200,000
Property, plant and equipment		(150,100,000)
Intangible assets		(8,000,000)
Deferred tax assets		(6,900,000)
Other assets		0
Goodwill		117,900,000
Total assets acquired		(20,300,000)
Accounts payable and accrued liabilities		1,200,000
Income tax payable		2,500,000
Other current liabilities		0
Long-term debt (including current and non-current portions)		0
Deferred tax liabilities		(6,000,000)
Other long-term liabilities		(12,300,000)
Net assets acquired		$ (5,700,000)

Acquisition of Apple Bidco Li_7

Acquisition of Apple Bidco Limited - Summary of Fair Values of Assets Acquired and Liabilities Assumed (Parenthetical) (Detail) - APR Energy [Member] $ in Millions	Feb. 28, 2020USD ($)
Business Acquisition [Line Items]
Business combination, acquired receivables, gross contractual amount	$ 57
Business combination, acquired receivables, amount not expected to be collected	$ 7.9

Acquisition of Apple Bidco Li_8

Acquisition of Apple Bidco Limited - Summary of Pro forma Financial Information (Detail) - APR Energy [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Revenue	$ 1,464.6	$ 1,452.9
Net earnings	$ 179.3	$ 454.4

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020Segment
Segment Reporting [Abstract]
Number of operating segments	2
Number of reportable segments	2

Segment Reporting - Financial I

Segment Reporting - Financial Information by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenue (note 5)	$ 1,421.1	$ 1,131.5	$ 1,096.3
Operating expense	274.8	229.8	219.3
Depreciation and amortization	353.9	254.3	245.8
General and administrative	65.4	33.1	31.6
Operating leases	150.5
Total segment adjusted EBITDA	922.5
Eliminations and other	(1.3)
Goodwill impairment (note 10)	117.9	0	0
Interest expense	191.6	218.9	212.1
Interest income	(5)
Income tax expense	16.6	1.2	$ 0.6
Loss on derivative instruments	35.5
Other expenses	8.6
Gain on contingent consideration asset	(6.8)
Loss on foreign currency repatriation	18.7
Loss on sale	0.2
Consolidated net earnings before taxes	209.2
Total assets	9,289.1	$ 7,917
Elimination and Other [Member]
Segment Reporting Information [Line Items]
Operating expense	0
Depreciation and amortization	0
General and administrative	(8.1)
Operating leases	0
Goodwill impairment (note 10)	0
Interest expense	(3.9)
Interest income	0
Income tax expense	0
Containership Leasing [Member]
Segment Reporting Information [Line Items]
Revenue (note 5)	1,222.8
Total segment adjusted EBITDA	795.5
Goodwill impairment (note 10)	0
Total assets	8,475.4
Capital expenditures	848.1
Containership Leasing [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue (note 5)	1,222.8
Operating expense	243.4
Depreciation and amortization	288.1
General and administrative	36.6
Operating leases	147.3
Goodwill impairment (note 10)	0
Interest expense	176
Interest income	(1.4)
Income tax expense	1
Mobile Power Generation [Member]
Segment Reporting Information [Line Items]
Revenue (note 5)	198.3
Total segment adjusted EBITDA	127
Goodwill impairment (note 10)	117.9
Total assets	829.9
Capital expenditures	17.6
Mobile Power Generation [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue (note 5)	198.3
Operating expense	31.4
Depreciation and amortization	65.8
General and administrative	36.9
Operating leases	3.2
Goodwill impairment (note 10)	117.9
Interest expense	19.5
Interest income	(3.6)
Income tax expense	15.6
Elimination And Other
Segment Reporting Information [Line Items]
Total assets	$ (16.2)

Revenue - Summary of Revenue Di

Revenue - Summary of Revenue Disaggregated by Segment and by Type (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	$ 1,421.1	$ 1,131.5	$ 1,096.3
Containership Leasing [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	1,222.8
Mobile Power Generation [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	198.3
Operating Lease Revenue [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	1,367.4	1,096	1,061.1
Operating Lease Revenue [Member] | Containership Leasing [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	1,180
Operating Lease Revenue [Member] | Mobile Power Generation [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	187.4
Interest Income From Leasing [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	40.5	$ 35.5	$ 35.2
Interest Income From Leasing [Member] | Containership Leasing [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	40.5
Interest Income From Leasing [Member] | Mobile Power Generation [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	0
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	13.2
Other [Member] | Containership Leasing [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	2.3
Other [Member] | Mobile Power Generation [Member]
Disaggregation Of Revenue [Line Items]
Revenue disaggregated by segment and by type	$ 10.9

Revenue - Schedule of Future Mi

Revenue - Schedule of Future Minimum Revenues Committed (Detail) $ in Millions	Dec. 31, 2020USD ($)
Operating lease revenue
2021	$ 1,354.1
2022	1,051.1
2023	722.9
2024	447.9
2025	264.6
Thereafter	274.6
Future minimum revenue to be received from operating leases	4,115.2
Direct financing leases
2021	36.1
2022	34.4
2023	32.5
2024	30.3
2025	28.2
Thereafter	180.7
Future interest income to be earned from direct financing leases	342.2
Other
2021	10
2022	4.1
2023	0.7
2024	0
2025	0
Thereafter	0
Future minimum revenue receivable other	14.8
Total committed revenue
2021	1,400.2
2022	1,089.6
2023	756.1
2024	478.2
2025	292.8
Thereafter	455.3
Future minimum revenues receivable	$ 4,472.2

Revenue - Schedule of Future _2

Revenue - Schedule of Future Minimum Revenues Received Based on Segment (Detail) $ in Millions	Dec. 31, 2020USD ($)
Segment Reporting Information Revenue [Line Items]
2021	$ 1,400.2
2022	1,089.6
2023	756.1
2024	478.2
2025	292.8
Thereafter	455.3
Future minimum revenues receivable	4,472.2
Containership Leasing [Member]
Segment Reporting Information Revenue [Line Items]
2021	1,243.1
2022	1,000.9
2023	718
2024	478.2
2025	292.8
Thereafter	455.3
Future minimum revenues receivable	4,188.3
Mobile Power Generation [Member]
Segment Reporting Information Revenue [Line Items]
2021	157.1
2022	88.7
2023	38.1
2024	0
2025	0
Thereafter	0
Future minimum revenues receivable	$ 283.9

Revenue - Additional Informatio

Revenue - Additional Information (Detail) - USD ($)	1 Months Ended
	Mar. 31, 2019	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Percentage of future minimum revenues utilization to be received		100.00%
Settlement payment received related to modification of time charters	$ 227,000,000

Revenue - Schedule of Revenue D

Revenue - Schedule of Revenue Derived from Customers (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
Revenue derived from customers	$ 1,421.1	$ 1,131.5	$ 1,096.3
COSCO [Member]
Disaggregation Of Revenue [Line Items]
Revenue derived from customers	401.1	407.4	412.3
Yang Ming Marine [Member]
Disaggregation Of Revenue [Line Items]
Revenue derived from customers	255.7	257.5	235.6
ONE [Member]
Disaggregation Of Revenue [Line Items]
Revenue derived from customers	237.3	199.4	241.6
Other [Member]
Disaggregation Of Revenue [Line Items]
Revenue derived from customers	$ 527	$ 267.2	$ 206.8

Related party transactions - Ad

Related party transactions - Additional Information (Detail) - USD ($)	Feb. 28, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 15, 2019	May 31, 2018	Mar. 13, 2018	Mar. 12, 2018	Feb. 14, 2018
Related Party Transaction [Line Items]
Shares held in reserve as treasury shares		727,351	37,778
Interest expense, excluding amortization of debt discount		$ 32,114,000	$ 26,927,000	$ 19,380,000
Amortization of debt discount		$ 19,963,000	$ 17,347,000	$ 7,310,000
APR Energy Ltd [Member]
Related Party Transaction [Line Items]
Shares issued	29,891,266
Holdback shares, forfeited		557,139
2027 Notes [Member]
Related Party Transaction [Line Items]
Face value of debt	$ 100,000,000
Debt instrument, interest rate	5.50%
GCI [Member]
Related Party Transaction [Line Items]
Percentage of equity method investment								10.80%
Percentage of interest in acquired entity							89.20%
Fairfax Financial Holdings Limited [Member]
Related Party Transaction [Line Items]
Warrants outstanding					38,461,539				38,461,539
Warrants outstanding exercise price					$ 6.50	$ 8.05			$ 6.50
Warrants to purchase common shares						25,000,000
Number of holdback shares reserved for issuance	2,137,541
Shares permanently forfeited	760,807
Shares held in reserve as treasury shares	493,076
Holdback shares, forfeited	391,246
Equity method investment ownership percentage		40.50%
Fairfax Financial Holdings Limited [Member] | APR Energy Ltd [Member]
Related Party Transaction [Line Items]
Shares issued	23,418,798	318,637
Common shares returned	1,253,883
Fairfax Financial Holdings Limited [Member] | Senior Notes Due 2025 [Member]
Related Party Transaction [Line Items]
Face value of debt									$ 250,000,000
Debt instrument, interest rate									5.50%
Fairfax Financial Holdings Limited [Member] | Senior Notes Due 2026 [Member]
Related Party Transaction [Line Items]
Face value of debt					$ 250,000,000
Debt instrument, interest rate					5.50%
Fairfax Financial Holdings Limited [Member] | 2027 Notes [Member]
Related Party Transaction [Line Items]
Face value of debt	$ 100,000,000
Debt instrument, interest rate	5.50%

Net investment in lease - Sched

Net investment in lease - Schedule of Net Investment in Lease (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Undiscounted lease receivable	$ 773.2	$ 1,224.2
Unearned interest income	(343.9)	(465.4)
Net investment in lease	$ 429.3	$ 758.8

Net investment in lease - Sch_2

Net investment in lease - Schedule of Net Investment in Lease (Detail 1) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lease receivables	$ 429.3	$ 608.8
Unguaranteed residual value	0	150
Net investment in lease	429.3	758.8
Current portion of net investment in lease	(10.7)	(35.2)
Long-term portion of net investment in lease	$ 418.6	$ 723.6

Net investment in lease - Addit

Net investment in lease - Additional Information (Detail)	1 Months Ended				6 Months Ended	12 Months Ended
	Feb. 29, 2020	Jan. 31, 2020Vessel	Dec. 31, 2019Vessel	Nov. 30, 2019Vessel	Jan. 31, 2018VesselTEU	Dec. 31, 2020USD ($)
Leases [Line Items]
Number of vessels				6	5
Capacity in TEUs | TEU					11,000
Term of agreement					17 years
Number of vessels delivered		1	5
Number of vessels acquired				6
Extended leases term	6 years
Impact on bareboat charters modification						In February 2020, the bareboat charters for the six vessels acquired in November 2019 were modified to extend the terms of the leases by six years, with similar purchase options. As a result of the modification, it was determined that the customer is no longer reasonably certain to exercise the purchase options and these leases were reclassified as operating leases.
MSC [Member]
Leases [Line Items]
Purchase price per vessel | $						$ 32,000,000

Net investment in lease - Sch_3

Net investment in lease - Schedule of Minimum Lease Receivable from Direct Financing Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 44.3
2022	44.3
2023	44.3
2024	44.5
2025	44.4
Thereafter	551.4
Minimum lease receivable from direct financing leases	$ 773.2	$ 1,224.2

Property, plant and equipment -

Property, plant and equipment - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Cost	$ 9,692	$ 8,023.1
Accumulated depreciation	(2,717.3)	(2,315.4)
Net book value	6,974.7	5,707.7
Vessels [Member]
Property Plant And Equipment [Line Items]
Cost	9,148.9	8,018.5
Accumulated depreciation	(2,571.3)	(2,311.4)
Net book value	6,577.6	5,707.1
Equipment and Other [Member]
Property Plant And Equipment [Line Items]
Cost	543.1	4.6
Accumulated depreciation	(146)	(4)
Net book value	$ 397.1	$ 0.6

Property, plant and equipment_2

Property, plant and equipment - Additional Information (Details)	1 Months Ended	12 Months Ended
	Feb. 29, 2020USD ($)BareboatCharter	Dec. 31, 2020USD ($)Vessel	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Property Plant And Equipment [Line Items]
Depreciation expense		$ 324,597,000	$ 233,729,000	$ 219,330,000
Payments to acquire property, plant & equipment		783,500,000	$ 332,500,000	$ 319,200,000
Number of bareboat charters re-assessed | BareboatCharter	6
Vessels [Member]
Property Plant And Equipment [Line Items]
Payments to acquire property, plant & equipment		$ 785,033,000
Reclassification to property, plant and equipment	$ 377,393,000
Number of secondhand vessels purchased | Vessel		10
Number of vessels reclassified to property, plant and equipment | Vessel		1
APR Energy [Member] | Gas Turbines and Other Equipment [Member]
Property Plant And Equipment [Line Items]
Payments to acquire property, plant & equipment	$ 447,166,000

Right-of-use assets - Schedule

Right-of-use assets - Schedule of Right-of-Use Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Lease Right Of Use Assets [Line Items]
Cost	$ 1,074.5	$ 1,069.1
Accumulated amortization	(233.3)	(111.9)
Net book value	841.2	957.2	$ 1,068.3	$ 0
Vessel Operating Leases [Member]
Operating Lease Right Of Use Assets [Line Items]
Cost	1,060.9	1,060.9
Accumulated amortization	(228)	(110.1)
Net book value	832.9	950.8
Other Operating Leases [Member]
Operating Lease Right Of Use Assets [Line Items]
Cost	13.6
Accumulated amortization	(5.3)
Net book value	$ 8.3
Office Operating Leases [Member]
Operating Lease Right Of Use Assets [Line Items]
Cost		8.2
Accumulated amortization		(1.8)
Net book value		$ 6.4

Right-of-use assets - Additiona

Right-of-use assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Lease Right Of Use Assets [Abstract]
Change in right-of-use asset	$ 120,140,000	$ 111,810,000	$ 0

Goodwill - Schedule of Goodwill

Goodwill - Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Balance, December 31, 2019	$ 75.3
Impairment loss recognized during the period	(117.9)	$ 0	$ 0
Balance, December 31, 2020	75.3	75.3
Containership Leasing [Member]
Goodwill [Line Items]
Balance, December 31, 2019	75.3
Goodwill arising from acquisition of APR Energy (note 3)	0
Impairment loss recognized during the period	0
Balance, December 31, 2020	75.3	75.3
Mobile Power Generation [Member]
Goodwill [Line Items]
Balance, December 31, 2019	0
Goodwill arising from acquisition of APR Energy (note 3)	117.9
Impairment loss recognized during the period	(117.9)
Balance, December 31, 2020	$ 0	$ 0

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) - USD ($) $ in Millions	Feb. 28, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Line Items]
Impairment loss		$ 117.9	$ 0	$ 0
APR Energy [Member]
Goodwill [Line Items]
Goodwill arising from acquisition of APR Energy (note 3)	$ 117,900,000
Impairment loss	$ 117,900,000

Other assets - Schedule of Othe

Other assets - Schedule of Other Assets (Detail) - USD ($) $ in Millions		Dec. 31, 2020		Dec. 31, 2019		Jan. 01, 2019	Dec. 31, 2018
Other Assets [Abstract]
Intangible assets	[1]	$ 104.8		$ 94
Deferred dry-dock		63.8	[2]	41.3	[2]		$ 36.7
Restricted cash	[3]	38.2		0
Contingent consideration asset	[4]	84		0
Vessels under construction	[5]	42		0
Other		42.9		37.2
Other assets		$ 375.7		$ 172.5		$ 187.6	$ 204.9
[1]	(a) Intangible assets: December 31, 2020 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (58.6 ) $ 71.3 Trademark 27.4 (1.1 ) 26.3 Other 11.5 (4.3 ) 7.2 $ 168.8 $ (64.0 ) $ 104.8 December 31, 2019 Cost Accumulated Amortization Net book value Customer contracts $ 129.9 $ (39.3 ) $ 90.6 Other 6.6 (3.2 ) 3.4 $ 136.5 $ (42.5 ) $ 94.0 As part of the acquisition of APR Energy on February 28, 2020, the Company recorded $27,400,000 related to the fair value of a trademark. The trademark is amortized on a straight-line basis over its estimated useful life of 20 years. Acquired customer contracts are amortized on a straight-line basis over their remaining useful lives. As of December 31, 2020, the weighted average remaining useful lives of acquired customer contracts was 5 years (2019 – 5 years). During the year ended December 31, 2020, the Company recorded $21,396,000 of amortization related to intangible assets (2019 – $20,729,000, 2018 – $16,569,000). Future amortization of intangible assets is as follows: 2021 $ 19.1 2022 18.2 2023 14.5 2024 11.7 2025 8.3 Thereafter 33.0 $ 104.8
[2]	(b) Deferred dry-dock: During the year ended December 31, 2020, changes in deferred dry-dock were as follows: December 31, 2018 36.7 Costs incurred 23.5 Amortization expensed (1) (18.9 ) December 31, 2019 41.3 Costs incurred 45.2 Amortization expensed (1) (22.7 ) December 31, 2020 $ 63.8 (1) Amortization of dry-docking costs is included in depreciation and amortization
[3]	(c) Restricted cash: Restricted cash consists primarily of amounts held in reserve accounts related to the Company’s debt facilities.
[4]	(d) Contingent consideration asset: As a part of the acquisition of APR Energy on February 28, 2020, the Company is compensated by the Sellers for certain losses that may be incurred on future cash repatriation from a foreign jurisdiction until the earlier of (1) reaching the maximum cash flows subject to compensation, (2) termination of specified contracts, (3) sustaining the ability to repatriate cash without losses and (4) April 30, 2022. The amount of compensation depends on the Company’s ability to generate cash flows on specific contracts in the foreign jurisdiction and the magnitude of losses incurred on repatriation. The maximum amount of cash flows subject to compensation is $110,000,000. Fairfax agreed, subject to definitive documentation, to compensate the Company for future losses realized on sale or disposal of certain property, plant and equipment and inventory items calculated as the difference between the proceeds on sale or disposal and the book value of the respective assets at February 28, 2020, prior to acquisition. The maximum amount of losses subject to compensation is $64,000,000. Contingent consideration asset, December 31, 2019 $ — Assets acquired 95.2 Change in fair value 6.8 Compensation received (11.1 ) Contingent consideration asset 90.9 Current portion included in prepaid expenses and other (6.9 ) Contingent consideration asset, December 31, 2020 $ 84.0
[5]	(e) Vessels under construction:

Other assets - Schedule of Ot_2

Other assets - Schedule of Other Assets (Parenthetical) (Detail)		Feb. 28, 2020USD ($)	Nov. 30, 2020USD ($)VesselInstallment	Dec. 31, 2020USD ($)		Dec. 31, 2019USD ($)		Dec. 31, 2018USD ($)
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Cost						$ 136,500,000
Accumulated Amortization						(42,500,000)
Net book value				$ 104,800,000		94,000,000
Amortization related to intangible asset				21,396,000		20,729,000		$ 16,569,000
2021				19,100,000
2022				18,200,000
2023				14,500,000
2024				11,700,000
2025				8,300,000
Thereafter				33,000,000
December 31, 2018				41,300,000	[1]	36,700,000
Costs incurred, Dry-docking				45,200,000		23,500,000
Amortization expensed, Dry-docking	[2]			(22,700,000)		(18,900,000)
Ending Balance, Dry-docking				63,800,000	[1]	41,300,000	[1]	$ 36,700,000
Contingent consideration asset, beginning balance	[3]			0
Assets acquired				95,200,000
Change in fair value				6,800,000
Compensation received				(11,100,000)
Contingent consideration asset				90,900,000
Current portion included in prepaid expenses and other				(6,900,000)
Contingent consideration asset, ending balance	[3]			84,000,000		0
Shipyard [Member] | 12000 TEU Vessels [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Number of vessels build | Vessel			5
Aggregate purchase price of vessels			$ 419,825,000
Number of payable installments | Installment			4
Amount of first installment paid				41,982,500
APR Energy [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Maximum amount of cash flows subject to compensation		$ 110,000,000
APR Energy [Member] | Fairfax Financial Holdings Limited [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Maximum amount of cash flows subject to compensation		$ 64,000,000
Customer Contracts [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Cost				129,900,000		129,900,000
Accumulated Amortization				(58,600,000)		(39,300,000)
Net book value				71,300,000		90,600,000
Trademark [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Cost				27,400,000
Accumulated Amortization				(1,100,000)
Net book value				$ 26,300,000
Trademark [Member] | APR Energy [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Estimated useful life of trademark				20 years
Trademark [Member] | APR Energy [Member] | Mobile Power Generation [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Fair value of trademark				$ 27,400,000
Other [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Cost				11,500,000		6,600,000
Accumulated Amortization				(4,300,000)		(3,200,000)
Net book value				$ 7,200,000		$ 3,400,000
Acquired Customer Contracts [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Weighted average remaining useful lives				5 years		5 years
[1]	(b) Deferred dry-dock: During the year ended December 31, 2020, changes in deferred dry-dock were as follows: December 31, 2018 36.7 Costs incurred 23.5 Amortization expensed (1) (18.9 ) December 31, 2019 41.3 Costs incurred 45.2 Amortization expensed (1) (22.7 ) December 31, 2020 $ 63.8 (1) Amortization of dry-docking costs is included in depreciation and amortization
[2]	Amortization of dry-docking costs is included in depreciation and amortization
[3]	(d) Contingent consideration asset: As a part of the acquisition of APR Energy on February 28, 2020, the Company is compensated by the Sellers for certain losses that may be incurred on future cash repatriation from a foreign jurisdiction until the earlier of (1) reaching the maximum cash flows subject to compensation, (2) termination of specified contracts, (3) sustaining the ability to repatriate cash without losses and (4) April 30, 2022. The amount of compensation depends on the Company’s ability to generate cash flows on specific contracts in the foreign jurisdiction and the magnitude of losses incurred on repatriation. The maximum amount of cash flows subject to compensation is $110,000,000. Fairfax agreed, subject to definitive documentation, to compensate the Company for future losses realized on sale or disposal of certain property, plant and equipment and inventory items calculated as the difference between the proceeds on sale or disposal and the book value of the respective assets at February 28, 2020, prior to acquisition. The maximum amount of losses subject to compensation is $64,000,000. Contingent consideration asset, December 31, 2019 $ — Assets acquired 95.2 Change in fair value 6.8 Compensation received (11.1 ) Contingent consideration asset 90.9 Current portion included in prepaid expenses and other (6.9 ) Contingent consideration asset, December 31, 2020 $ 84.0

Long-term Debt - Schedule of Lo

Long-term Debt - Schedule of Long-Term Debt (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, gross	$ 3,748,100,000	$ 3,246,400,000
Deferred financing fees	(44,900,000)	(34,800,000)
Long-term debt	3,566,100,000	3,060,600,000
Current portion of long-term debt	(332,100,000)	(363,700,000)
Long-term debt Non Current	3,234,000,000	2,696,900,000
Revolving Credit Facilities [Member]
Debt Instrument [Line Items]
Long-term debt, gross	772,100,000	867,000,000
Long-term debt	772,100,000
Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Long-term debt, gross	2,094,700,000	1,799,400,000
Fair value adjustment on term loan credit facilities	(100,000)	(100,000)
Long-term debt	2,094,700,000
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross	80,000,000	80,000,000
Long-term debt	80,000,000	80,000,000
Exchangeable Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross	201,300,000	0
Debt discount on notes	(6,100,000)	0
Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Long-term debt, gross	600,000,000	500,000,000
Debt discount on notes	$ (130,900,000)	$ (150,900,000)

Long-term Debt - Additional Inf

Long-term Debt - Additional Information (Detail)	Dec. 21, 2020USD ($)$ / sharesshares	Oct. 15, 2020USD ($)	Jul. 02, 2020USD ($)	Mar. 06, 2020USD ($)	Feb. 28, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)VesselCreditFacility$ / shares	Dec. 31, 2019USD ($)CreditFacility	Dec. 14, 2020USD ($)
Debt Instrument [Line Items]
Long-term debt, gross							$ 3,748,100,000	$ 3,246,400,000
Maturity date							Mar. 1, 2027
Number of vessels secured by first-priority mortgages | Vessel							70
Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Long-term debt, gross							$ 600,000,000	$ 500,000,000
Senior Unsecured Notes Due 2019 [Member]
Debt Instrument [Line Items]
Maturity date								Apr. 30, 2019
Debt instrument, interest rate								6.375%
Repayment of principal balance of term loan								$ 320,396,000
Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Maturity date							Oct. 30, 2027
Debt instrument, interest rate							7.125%
2027 Notes [Member]
Debt Instrument [Line Items]
Principal outstanding amount					$ 100,000,000
Interest bearing of aggregate principal amount					5.50%
2027 Notes [Member] | Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Principal outstanding amount					$ 100,000,000
Interest bearing of aggregate principal amount					5.50%
Fairfax Notes [Member] | Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Percentage of principal amount redeemed							100.00%
Exchangeable Notes [Member]
Debt Instrument [Line Items]
Maturity date							Dec. 15, 2025
Principal outstanding amount	$ 201,250,000
Interest bearing of aggregate principal amount	3.75%
Percentage of principal amount redeemed							100.00%
Aggregate shares | shares	15,474,817
Initial exchange price per share | $ / shares	$ 13.005
Trading price per principal amount	$ 1,000
Debt instrument redemption start date							Dec. 20, 2023
Debt instrument redemption end date							Sep. 15, 2025
Debt instrument redemption description							The Company may redeem the Exchangeable Notes in connection with certain tax-related events or on any business day on or after December 20, 2023 and prior to September 15, 2025, if the last reported sale price of an Atlas common share is at least 130% of the exchange price during a specified measurement period. A redemption of the Exchangeable Notes is made at 100% of the principal amount, plus accrued and unpaid interest.
Minimum percentage of common stock price to conversion price							130.00%
Proceeds from issuance of debt							$ 15,536,000
Debt instrument effective interest rate							4.50%
Debt Instrument Periodic Payment Interest Description							Interest payment is semi-annually in arrears on June 15 and December 15 of each year, beginning on June 15, 2021.
Common share maximum capped price to exercise capped call | $ / shares							$ 17.85
Exchangeable Notes [Member] | Fair Value [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt							$ 195,000,000
Exchangeable Notes [Member] | Residual Value [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt							6,250,000
Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Credit facilities, maximum aggregate borrowings							2,344,730,000	1,954,375,000
Credit facilities, aggregate borrowings undrawn							250,000,000	155,000,000
Long-term debt, gross							$ 2,094,700,000	$ 1,799,400,000
Weighted average rate of interest, including the margin							2.70%	4.00%
Debt instrument, interest rate							7.70%	7.70%
Term Loan Credit Facilities [Member] | Export-Import Bank Of Korea [Member]
Debt Instrument [Line Items]
Interest rate margin							0.70%	0.70%
Principal outstanding amount							$ 39,970,000	$ 52,743,000
Sustainability-linked Term Loan Facility [Member]
Debt Instrument [Line Items]
Credit facilities, maximum aggregate borrowings		$ 200,000,000
Maturity date		Oct. 14, 2026
Debt instrument, interest rate		2.25%
Line of credit facility subsequently upsized amount									$ 250,000,000
Amounts drawn under facility							$ 0
Maximum [Member]
Debt Instrument [Line Items]
Credit facilities, increase in maximum aggregate borrowings			$ 200,000,000
Maximum [Member] | Fairfax Notes [Member] | Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Notice period required for early redemption of notes							150 days
Maximum [Member] | Exchangeable Notes [Member]
Debt Instrument [Line Items]
Percentage of eligible trading price per share for exchangeable notes	98.00%
Minimum [Member] | Fairfax Notes [Member] | Fairfax Financial Holdings Limited [Member]
Debt Instrument [Line Items]
Notice period required for early redemption of notes							120 days
Minimum [Member] | Exchangeable Notes [Member]
Debt Instrument [Line Items]
Percentage of eligible share price for exchangeable notes	130.00%
Revolving Credit Facilities [Member]
Debt Instrument [Line Items]
Number of long-term revolving credit facilities | CreditFacility							5	4
Credit facilities, maximum aggregate borrowings			$ 150,000,000		$ 185,000,000		$ 989,119,000	$ 987,012,000
Credit facilities, aggregate borrowings undrawn							217,000,000	120,000,000
Long-term debt, gross							$ 772,100,000	$ 867,000,000
Maturity date			Jul. 2, 2022		Feb. 28, 2023		Dec. 31, 2023
Revolving credit facilities, maturity date range, start							Dec. 31, 2022
Revolving credit facilities, maturity date range, end							May 15, 2024
Debt instrument description							As at December 31, 2020, the one month, three month and six month average LIBOR on the Company’s revolving credit facilities was 0.2%, 0.2% and 0.3%, respectively (December 31, 2019 – one month and three months average LIBOR of 1.8% and 1.9%, respectively) and the margins ranged between 0.5% and 2.25% (December 31, 2019 – 0.5% and 2.25%).
Weighted average rate of interest, including the margin							1.40%	2.90%
Description of the terms of a credit facility arrangement							For one of the revolving credit facilities, semi-annual payments commence thirty-six months after delivery of the associated newbuild containership for the facility.
Revolving Credit Facilities [Member] | Term Loan Payment Due in Full Maturity [Member]
Debt Instrument [Line Items]
Principal outstanding amount							$ 58,240,000
Revolving Credit Facilities [Member] | Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument description							For all of the Company’s term loan credit facilities, except for one, interest is calculated based on three month or six month LIBOR plus a margin per annum, dependent on the interest period selected by the Company. The three month and six month average LIBOR was 0.2% and 0.3%, respectively (December 31, 2019 – 2.0% and 2.1%) and the margins ranged between 0.4% and 4.3% as at December 31, 2020 (December 31, 2019 – 0.4% and 4.3%).
Principal outstanding amount							$ 1,582,470,000
Number of vessels secured by first-priority mortgages | Vessel							48
Revolving Credit Facilities [Member] | One Month LIBOR [Member]
Debt Instrument [Line Items]
LIBOR interest rate							0.20%	1.80%
Revolving Credit Facilities [Member] | Three Month LIBOR [Member]
Debt Instrument [Line Items]
LIBOR interest rate							0.20%	1.90%
Revolving Credit Facilities [Member] | Three Month LIBOR [Member] | Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
LIBOR interest rate							0.20%	2.00%
Revolving Credit Facilities [Member] | Six Month LIBOR [Member]
Debt Instrument [Line Items]
LIBOR interest rate							0.30%
Revolving Credit Facilities [Member] | Six Month LIBOR [Member] | Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
LIBOR interest rate							0.30%	2.10%
Revolving Credit Facilities [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate margin							2.25%	2.25%
Commitment fee on undrawn amount							0.60%	0.50%
Revolving Credit Facilities [Member] | Maximum [Member] | Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Interest rate margin							4.30%	4.30%
Revolving Credit Facilities [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate margin							0.50%	0.50%
Commitment fee on undrawn amount							0.20%	0.20%
Revolving Credit Facilities [Member] | Minimum [Member] | Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Interest rate margin							0.40%	0.40%
Revolving Loan Facility [Member]
Debt Instrument [Line Items]
Long-term debt, gross					$ 50,000,000
Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
Long-term debt, gross				$ 100,000,000	$ 135,000,000
Maturity date				Mar. 6, 2026
Revolving credit facilities, maturity date range, start							Dec. 23, 2021
Revolving credit facilities, maturity date range, end							Jan. 21, 2030
Debt instrument, interest rate				7.70%
Term Loan Credit Facilities [Member] | Term Loan Credit Facilities Matures on December 30, 2025 [Member]
Debt Instrument [Line Items]
Term loan credit facilities increase in carrying amount						$ 100,000,000
Revolving Credit Facilities Two [Member]
Debt Instrument [Line Items]
Maturity date							May 15, 2022
Description of the terms of a credit facility arrangement							revolving credit facility with a principal outstanding of $283,000,000, will be converted into a term loan facility on May 15, 2022.
Principal outstanding amount							$ 283,000,000

Long-term Debt - Schedule of Fu

Long-term Debt - Schedule of Future Minimum Repayments Under Revolving Credit Facilities and Term Loans (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt	$ 3,566.1	$ 3,060.6
Term Loan Credit Facilities [Member]
Debt Instrument [Line Items]
2021	286.1
2022	187.9
2023	364.5
2024	877.2
2025	222.7
Thereafter	156.3
Long-term debt	2,094.7
Revolving Credit Facilities [Member]
Debt Instrument [Line Items]
2021	50.7
2022	392.2
2023	82.2
2024	247
2025	0
Thereafter	0
Long-term debt	$ 772.1

Operating lease liabilities - S

Operating lease liabilities - Schedule of Operating Lease Liabilities (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease commitments	$ 927,000,000	$ 1,107,600,000
Impact of discounting	(141,500,000)	(184,400,000)
Impact of changes in variable rates	44,700,000	19,100,000
Operating lease liabilities	830,200,000	942,308,000	$ 893,300,000	$ 0
Current portion of operating lease liabilities	(160,900,000)	(159,700,000)	$ (160,200,000)	$ 0
Operating lease liabilities	$ 669,300,000	$ 782,600,000

Operating lease liabilities -_2

Operating lease liabilities - Schedule of Operating Lease Costs Related To Vessel Sale-leaseback Transactions And Other Leases (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease costs:
Operating lease costs	$ 166.5	$ 160
Variable lease adjustments	(12.4)	(3)
Other information:
Operating cash outflow used for operating leases	$ 147.8	$ 153.2
Weighted average discount rate	4.80%	4.80%
Weighted average remaining lease term	7 years	8 years

Other Financing Arrangements -

Other Financing Arrangements - Schedule of Other Financing Arrangements (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Other financing arrangements	$ 879,468,000	$ 513,771,000
Deferred financing fees	(13,700,000)	(5,300,000)
Other financing arrangements	865,800,000	508,500,000
Current portion of other financing arrangements	(64,100,000)	(134,600,000)
Other financing arrangements	$ 801,700,000	$ 373,900,000

Other Financing Arrangements _2

Other Financing Arrangements - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Oct. 31, 2020USD ($)	Jan. 31, 2020USD ($)	Dec. 31, 2020USD ($)Vessel	Dec. 31, 2019
Sale Leaseback Transaction [Line Items]
Weighted average rate of interest, including the margin			3.12%	5.25%
COSCO Faith - 13100 TEU vessel [Member]
Sale Leaseback Transaction [Line Items]
Financing from counterparty			$ 109,000,000
Terms of leases			12 years
Lease payments include an interest component based on three month LIBOR plus margin percentage			3.00%
Amount of option to purchase the vessel from the lessor			$ 1
Prepayment on remaining balances of lease term		$ 48,316,000
Leases for three 4500 TEU vessels [Member]
Sale Leaseback Transaction [Line Items]
Terms of leases			5 years
Lease financing, number of vessels | Vessel			3
Refinancing from counterparty			$ 150,000,000
11000 TEU Newbuilding Vessels [Member]
Sale Leaseback Transaction [Line Items]
Financing from counterparty			$ 420,750,000
Terms of leases			17 years
Lease payments include an interest component based on three month LIBOR plus margin percentage			3.30%
Prepayment on remaining balances of lease term	$ 71,084,000
Lease financing, number of vessels | Vessel			5
Leases for four 12000 TEU vessels [Member]
Sale Leaseback Transaction [Line Items]
Financing from counterparty			$ 337,732,000
Terms of leases			10 years
Lease payments include an interest component based on three month LIBOR plus margin percentage			2.75%
Lease financing, number of vessels | Vessel			4
Leases for Two 13000 TEU Vessels [Member]
Sale Leaseback Transaction [Line Items]
Financing from counterparty			$ 138,225,000
Terms of leases			10 years
Lease payments include an interest component based on three month LIBOR plus margin percentage			2.75%
Lease financing, number of vessels | Vessel			2
Leases for Two 12000 TEU Vessels [Member]
Sale Leaseback Transaction [Line Items]
Financing from counterparty			$ 158,400,000
Lease payments include an interest component based on three month LIBOR plus margin percentage			2.75%
Lease financing, number of vessels | Vessel			2
Leases for Two 12000 TEU Vessels [Member] | Minimum [Member]
Sale Leaseback Transaction [Line Items]
Terms of leases			10 years
Leases for Two 12000 TEU Vessels [Member] | Maximum [Member]
Sale Leaseback Transaction [Line Items]
Terms of leases			12 years

Other Financing Arrangements _3

Other Financing Arrangements - Schedule of Repayments Due for Other Financing Arrangements (Detail) $ in Millions	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 64.6
2022	64.6
2023	64.6
2024	64.6
2025	57.4
Thereafter	563.7
Total	$ 879.5

Other liabilities - Schedule of

Other liabilities - Schedule of Other Long-Term Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Other Long Term Liabilities [Abstract]
Asset retirement obligations	$ 42.3	$ 0
Other	23.4	19
Other long-term liabilities	65.7	19
Current portion of other long-term liabilities	(24.8)	(7.8)	$ (10)	$ (32.2)
Other long-term liabilities	$ 40.9	$ 11.2	$ 22.2	$ 181.1

Other liabilities - Schedule _2

Other liabilities - Schedule of Changes in Asset Retirement Obligations (Detail) - APR Energy [Member] $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Asset Retirement Obligation [Line Items]
Asset retirement obligations, beginning balance	$ 0
Liabilities acquired	45.9
Liabilities incurred	5.3
Liabilities settled	(6.6)
Provision reassessment	(2.9)
Accretion expense	0.6
Asset retirement obligations, ending balance	$ 42.3

Income Tax - Schedule of Income

Income Tax - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current tax
Current tax expense	$ 20.2
Current income tax expense	20.2
Current tax expense, Foreign	20.2
Deferred tax
Deferred tax expense	(3.6)
Deferred income tax expense	(3.6)
Total tax expense	16.6	$ 1.2	$ 0.6
Deferred tax expense, Foreign	(3.6)
Foreign
Current tax
Current income tax expense	20.2
Deferred tax
Deferred income tax expense	(3.6)
Total tax expense	$ 16.6

Income Tax - Additional Informa

Income Tax - Additional Information (Details) - USD ($)	Mar. 27, 2020	Dec. 31, 2020	Dec. 31, 2019
Income Tax [Line Items]
Effective income tax rate reconciliation, at Federal statutory income tax rate, Percent		7.94%
Deferred tax assets		$ 34,700,000	$ 0
Deferred tax liabilities		$ 15,400,000	0
Income tax examination description		Tax years that remain open to examination by some of the major jurisdictions in which the Company is subject to tax range from two to four years
Income tax payable		$ 110,400,000	0
Unrecognized tax benefits that would affect effective tax rate		1,200,000
Unrecognized tax benefits		76,600,000	$ 0
Net operating loss carryovers and carrybacks percentage of taxable income	100.00%
Foreign
Income Tax [Line Items]
Tax losses carried forward		207,800,000
Deferred tax assets recognized		0
Income tax benefit expected to arise tax losses		$ 0
Percentage of tax losses offset by valuation allowance		100.00%
UK
Income Tax [Line Items]
Effective income tax rate reconciliation, Foreign income tax rate, Percent		19.00%

Income Tax - Reconciliation bet

Income Tax - Reconciliation between Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Computed tax expense on income from continuing operations	$ 39.7
Certain income from containership leasing segment that is exempt from tax	(58)
Goodwill impairment not deductible for tax	22.4
Change in valuation allowance	25.4
Change in current year uncertain tax positions	1.2
Change in tax law	(0.1)
Foreign rate differential	(26.8)
Withholding taxes	7.8
Other, net	5
Total tax expense	$ 16.6	$ 1.2	$ 0.6

Income Tax - Schedule of Deferr

Income Tax - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Decommission provisions	$ 16,600,000
Property, plant and equipment	25,900,000
Reserves and accrued expenses	63,900,000
Tax losses carried forward	40,400,000
Interest allowance	16,800,000
Deferred revenue	400,000
Valuation allowance	(129,300,000)
Deferred tax assets, Net	34,700,000	$ 0
Deferred tax liabilities
Deferred job costs	(3,800,000)
Accelerated asset costs	(2,700,000)
Inflation adjustment	(5,200,000)
Other timing differences	(3,700,000)
Deferred tax liabilities, Net	(15,400,000)	$ 0
Net deferred tax asset	$ 19,300,000

Income Tax - Summary of Unrecog

Income Tax - Summary of Unrecognized Tax Benefits (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Income Tax Uncertainties [Abstract]
Beginning Balance	$ 0
Acquired as part of APR Energy acquisition (note 3)	75,400,000
Decreases due to tax provisions expired	1,200,000
Ending Balance	$ 76,600,000

Preferred shares and share ca_3

Preferred shares and share capital - Additional Information (Detail) - $ / shares	Feb. 28, 2020	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common shares, authorized		400,000,000	400,000,000
Common shares, par value		$ 0.01	$ 0.01
Dividend reinvestment program discount rate percentage		3.00%
Fairfax Warrants [Member] | Class A Common Shares [Member]
Class Of Stock [Line Items]
Warrants to purchase common shares		25,000,000
Warrants outstanding exercise price		$ 8.05
Warrant exercisable period		7 years
Fairfax Financial Holdings Limited [Member]
Class Of Stock [Line Items]
Warrants to purchase common shares		5,000,000
Warrants outstanding exercise price		$ 13
APR Energy Ltd [Member]
Class Of Stock [Line Items]
Shares issued	29,891,266
Business acquisition equity interests, shares reserved	6,664,270
Common shares previously issued		1,849,641
Shares forfeited		557,139
Shares permanently forfeited for post closing purchase price adjustments		1,122,290
Treasury shares		727,351
Common shares released from holdback		318,637
APR Energy Ltd [Member] | Fairfax Financial Holdings Limited [Member]
Class Of Stock [Line Items]
Shares issued	775,139

Preferred shares and share ca_4

Preferred shares and share capital - Schedule of Preferred Shares Outstanding (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Preferred shares, authorized	150,000,000	150,000,000
Preferred shares, issued	33,335,570	33,335,570
Series D Preferred Shares [Member]
Class Of Stock [Line Items]
Preferred shares, authorized	20,000,000
Preferred shares, issued	5,093,728
Dividend rate per annum	7.95%
Redemption by Company permitted on or after	Jan. 30, 2018
Liquidation preference	$ 127,300	$ 127,300
Series E Preferred Shares [Member]
Class Of Stock [Line Items]
Preferred shares, authorized	15,000,000
Preferred shares, issued	5,415,937
Dividend rate per annum	8.25%
Redemption by Company permitted on or after	Feb. 13, 2019
Liquidation preference	$ 135,400	135,400
Series G Preferred Shares [Member]
Class Of Stock [Line Items]
Preferred shares, authorized	15,000,000
Preferred shares, issued	7,800,800
Dividend rate per annum	8.20%
Redemption by Company permitted on or after	Jun. 16, 2021
Liquidation preference	$ 195,000	195,000
Series H Preferred Shares [Member]
Class Of Stock [Line Items]
Preferred shares, authorized	15,000,000
Preferred shares, issued	9,025,105
Dividend rate per annum	7.875%
Redemption by Company permitted on or after	Aug. 11, 2021
Liquidation preference	$ 225,600	225,600
Series I Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred shares, authorized	6,000,000
Preferred shares, issued	6,000,000
Dividend rate per annum	8.00%
Redemption by Company permitted on or after	Oct. 30, 2023
Liquidation preference	$ 150,000	$ 150,000

Preferred shares and share ca_5

Preferred shares and share capital - Schedule of Preferred Shares Outstanding (Parenthetical) (Detail)	Dec. 31, 2020$ / shares
Equity [Abstract]
Redemption price per share	$ 25

Earnings per share ("EPS") - Sc

Earnings per share ("EPS") - Schedule of Reconciliation of Numerator and Denominator Used in Basic and Diluted EPS Computations (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share Basic [Line Items]
Net earnings	$ 192.6	$ 439.1	$ 278.8
Net earnings attributable to common shareholders, basic	125.5	368	207.5
Share-based compensation, shares	0	0	0
Fairfax warrants, shares	0	0	0
Holdback shares, shares	0
Net earnings attributable to common shareholders, diluted	$ 125.5	$ 368	$ 207.5
Net earnings attributable to common shareholders, basic shares	241,502,000	214,499,000	154,848,000
Share-based compensation	541,000	471,000	91,000
Fairfax warrants	3,096,000	4,902,000	3,129,000
Holdback shares	5,375,000
Net earnings attributable to common shareholders, diluted shares	250,514,000	219,872,000	158,068,000
Net earnings attributable to common shareholders, per share basic amount	$ 0.52	$ 1.72	$ 1.34
Net earnings attributable to common shareholders, per share diluted amount	$ 0.50	$ 1.67	$ 1.31
Series D Preferred Shares [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends	$ (10.1)	$ (14.1)	$ (14.6)
Series E Preferred Shares [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends	(11.2)	(11.2)	(11.2)
Series F Preferred Shares [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends			(8.3)
Series G Preferred Shares [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends	(16)	(16)	(16)
Series H Preferred Shares [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends	(17.8)	(17.8)	(17.8)
Series I Preferred Stock [Member]
Earnings Per Share Basic [Line Items]
Preferred share dividends	$ (12)	$ (12)	$ (3.4)

Share-based compensation - Addi

Share-based compensation - Additional Information (Detail)	Jan. 01, 2021shares	Sep. 30, 2020shares	Jun. 30, 2020Tranche$ / sharesshares	Jan. 31, 2018$ / sharesshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	May 31, 2020shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved for issuance under the plan			10,000,000					5,000,000
Remaining shares left for issuance under this plan					1,993,398	1,291,076
Share-based compensation expenses | $					$ 7,068,000	$ 3,310,000	$ 2,989,000
Total unrecognized compensation costs relating to unvested share-based compensation awards | $					$ 22,334,000	$ 3,764,000
Expected to be recognized over a weighted average period					29 months	29 months
Vesting period			5 years
Stock options, vesting description			The stock options vest in five tranches annually over five years beginning December 31, 2021 and expire on June 24, 2030
Vesting tranche | Tranche			5
Stock options, vesting start date			Dec. 31, 2021
Shares issuable upon exercise of options			1,500,000
Stock options, exercise price | $ / shares			$ 7.80
Expiration date			Jun. 24, 2030
Restricted shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period					1 year
Granted, stock units					1,051,492	67,400	164,326
Number of shares, Granted					1,051,492	67,400	164,326
Restricted shares [Member] | Board of Directors [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, stock units					1,051,492
Share based compensation, requisite service period ending date					Dec. 31, 2022
Number of shares, Granted					1,051,492
Restricted shares [Member] | Board of Directors [Member] | Requisite Service Period Ending on December 31,2022 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining shares expected to vest					1,000,000
Restricted shares [Member] | Board of Directors [Member] | Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining shares expected to vest	51,492
Remaining shares expected to vest, vesting date	Jan. 1, 2021
Phantom share units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period					3 years
Granted, stock units					0	0	30,000
Number of shares, Granted					0	0	30,000
Restricted stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, stock units					1,824,786	249,732	609,248
Stock options, vesting description					The restricted stock units generally vest over two or five years, in equal tranches
Number of shares, Granted					1,824,786	249,732	609,248
Restricted stock units [Member] | Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			5 years
Granted, stock units			1,500,000
Stock options, vesting description			The restricted stock units vest in five tranches annually over five years beginning December 31, 2021 and have a grant date fair value of $7.25 per unit
Number of shares, Granted			1,500,000
Vesting tranche | Tranche			5
Stock options, vesting start date			Dec. 31, 2021
Weighted average grant date fair value | $ / shares			$ 7.25
Restricted stock units [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Restricted stock units, forfeitures		71,799
Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, stock units					1,500,000	0	500,000
Number of shares, Granted					1,500,000	0	500,000
Stock options [Member] | Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, vesting description				The stock options vest equally on each of the first five anniversaries of the CEO’s start date in January 2018 and expire on January 8, 2028
Stock options, vesting start date				Jan. 31, 2018
Expiration date				Jan. 8, 2028
Stock options [Member] | Chief Executive Officer [Member] | Class A Common Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issuable upon exercise of options				500,000
Stock options, exercise price | $ / shares				$ 7.20

Share-based compensation - Summ

Share-based compensation - Summary of Outstanding Restricted Shares, Phantom Share Units, Stock Appreciation Rights and Restricted Stock Units (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Beginning balance	67,400	85,742	94,533
Number of shares, Granted	1,051,492	67,400	164,326
Number of shares, Vested and exercised	(67,400)	(85,742)	(119,509)
Number of shares, Expired			0
Number of shares, Cancelled	0	0	(53,608)
Number of shares, Ending balance	1,051,492	67,400	85,742
Number of shares, Vested and exercisable	0
W.A. grant date FV, Beginning balance	$ 8.15	$ 7.28	$ 8.89
W.A. grant date FV, Granted	7.84	8.15	7.19
W.A. grant date FV, Vested and exercised	8.15	7.28	8.52
W.A. grant date FV, Expired			0
W.A. grant date FV, Cancelled	0	0	7.10
W.A. grant date FV, Ending balance	7.84	$ 8.15	$ 7.28
W.A. grant date FV, Vested and exercisable	$ 0
Phantom share units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Beginning balance	507,001	567,002	727,001
Number of shares, Granted	0	0	30,000
Number of shares, Vested and exercised	(20,000)	(60,001)	(113,333)
Number of shares, Expired			0
Number of shares, Cancelled	0	0	(76,666)
Number of shares, Ending balance	487,001	507,001	567,002
Number of shares, Vested and exercisable	487,001
W.A. grant date FV, Beginning balance	$ 12.53	$ 12.97	$ 13.60
W.A. grant date FV, Granted	0	0	6.86
W.A. grant date FV, Vested and exercised	6.85	16.68	18.80
W.A. grant date FV, Expired			0
W.A. grant date FV, Cancelled	0	0	7.90
W.A. grant date FV, Ending balance	12.76	$ 12.53	$ 12.97
W.A. grant date FV, Vested and exercisable	$ 12.76
Stock appreciation rights (SARs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Beginning balance	0	0	485,974
Number of shares, Granted	0	0	0
Number of shares, Vested and exercised	0	0	0
Number of shares, Expired			(485,974)
Number of shares, Cancelled	0	0	0
Number of shares, Ending balance	0	0	0
Number of shares, Vested and exercisable	0
W.A. grant date FV, Beginning balance	$ 0	$ 0	$ 3.40
W.A. grant date FV, Granted	0	0	0
W.A. grant date FV, Vested and exercised	0	0	0
W.A. grant date FV, Expired			3.40
W.A. grant date FV, Cancelled	0	0	0
W.A. grant date FV, Ending balance	0	$ 0	$ 0
W.A. grant date FV, Vested and exercisable	$ 0
Restricted stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Beginning balance	576,964	584,771	71,184
Number of shares, Granted	1,824,786	249,732	609,248
Number of shares, Vested and exercised	(313,231)	(224,073)	(83,220)
Number of shares, Expired			0
Number of shares, Cancelled	(79,635)	(33,466)	(12,441)
Number of shares, Ending balance	2,008,884	576,964	584,771
Number of shares, Vested and exercisable	0
W.A. grant date FV, Beginning balance	$ 8.01	$ 7.91	$ 7.80
W.A. grant date FV, Granted	7.83	8.90	8.18
W.A. grant date FV, Vested and exercised	9.32	8.59	9.87
W.A. grant date FV, Expired			0
W.A. grant date FV, Cancelled	9.84	9.05	7.28
W.A. grant date FV, Ending balance	7.57	$ 8.01	$ 7.91
W.A. grant date FV, Vested and exercisable	$ 0
Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, Beginning balance	500,000	500,000	0
Number of shares, Granted	1,500,000	0	500,000
Number of shares, Vested and exercised	0	0	0
Number of shares, Expired			0
Number of shares, Cancelled	0	0	0
Number of shares, Ending balance	2,000,000	500,000	500,000
Number of shares, Vested and exercisable	200,000
W.A. grant date FV, Beginning balance	$ 2.45	$ 2.45	$ 0
W.A. grant date FV, Granted	2.57	0	2.45
W.A. grant date FV, Vested and exercised	0	0	0
W.A. grant date FV, Expired			0
W.A. grant date FV, Cancelled	0	0	0
W.A. grant date FV, Ending balance	2.51	$ 2.45	$ 2.45
W.A. grant date FV, Vested and exercisable	$ 2.54

Other information - Schedule of

Other information - Schedule of Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Payables And Accruals [Line Items]
Accounts payable and accrued liabilities, Total	$ 134.1	$ 83.4	$ 67.7	$ 70.2
Seaspan [Member]
Payables And Accruals [Line Items]
Accrued interest	17.2	17.1
Accounts payable and other accrued liabilities	116.9	66.3
Accounts payable and accrued liabilities, Total	$ 134.1	$ 83.4

Other information - Schedule _2

Other information - Schedule of Supplemental Cash Flow Information (Detail) - Seaspan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Line Items]
Interest paid	$ 156.2	$ 183.1	$ 194.3
Interest received	5	8.9	3.7
Undrawn credit facility fee paid	0.8	1.7	0.6
Income taxes paid	16.8	0	0
Non-cash investing and financing transactions:
Dividend reinvestment	0.3	1.2	22.8
Arrangement and transaction fee settled in shares	0	0	2.3
Commencement of sales-type lease	57	316.7	0
Issuance of warrants	0	0	67.5
Reclassification on lease modification	377.4	0	0
Liabilities incurred	5.3	0	0
ARO provision re-assessment	2.9	0	0
Refinancing of existing term loan credit facilities with draws made on new debt	0	302.7	0
Right-of-use assets arising from new operating leases	1.2	0.7	0
Prepayments transferred to property, plant and equipment upon vessel delivery	46.8	0	0
Changes in operating assets and liabilities
Accounts receivable	(17.1)	(2.3)	15.5
Inventories	(5.9)	6.3	0.5
Prepaids expenses and other	(10.3)	(0.9)	17
Net investment in lease	13.3	9.3	44.3
Accounts payable and accrued liabilities	(16.4)	11.5	(7)
Settlement of decommissioning provisions	(5.9)	0	0
Deferred revenue	8.4	(0.6)	(46.8)
Income tax payable	3.9	0	0
Major maintenance	(54.6)	(22.3)	(10.3)
Other liabilities	(8.6)	0	(1.5)
Operating lease liabilities	(114.7)	(111.9)	0
Derivative instruments	22.5	55	42
Contingent consideration asset	18.7	0	0
GCI [Member]
Non-cash investing and financing transactions:
Carrying value of previously held equity in GCI settled on acquisition	0	0	61.9
Issuance of shares on acquisition	0	0	13.9
Settlement of GCI transaction fees paid by the Company	0	0	15.2
Settlement of loans to affiliate, accrued interest and other intercompany balances on GCI acquisition	0	0	38.8
GCI [Member] | Series D Preferred Shares [Member]
Non-cash investing and financing transactions:
Issuance of shares on acquisition	0	0	47.2
APR Energy [Member]
Non-cash investing and financing transactions:
Issuance of shares on acquisition	316.8	0	0
APR Energy loans settled in shares	8.3	0	0
Holdback Shares	70.6	0	0
Purchase price adjustment related to APR Energy acquisition	4.5	0	0
Contingent consideration asset related to APR Energy acquisition	95.2	0	0
Net assets acquired on APR Energy acquisition	287.7	0	0
Cancellation of common shares issued on APR Energy acquisition	$ 12.5	$ 0	$ 0

Other information - Schedule _3

Other information - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Information [Line Items]
Cash and cash equivalents	$ 304.3	$ 195
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	342.5	197.3	$ 371.4	$ 267.2
Seaspan [Member]
Supplemental Cash Flow Information [Line Items]
Cash and cash equivalents	304.3	195	357.3
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	342.5	197.3	371.4
Seaspan [Member] | Prepaid and Other [Member]
Supplemental Cash Flow Information [Line Items]
Restricted cash	0	2.3	0
Seaspan [Member] | Other Assets [Member]
Supplemental Cash Flow Information [Line Items]
Restricted cash	$ 38.2	$ 0	$ 14.1

Commitments and contingencies -

Commitments and contingencies - Additional Information (Detail)	1 Months Ended	12 Months Ended
	Nov. 30, 2020USD ($)InstallmentContainership	Dec. 31, 2020USD ($)
Other Commitments [Line Items]
Operating leases, future minimum payments due		$ 927,000,000
Purchase commitment for aggregate purchase price		377,800,000
Letters of credit outstanding		11,686,000
Vessels [Member]
Other Commitments [Line Items]
Operating leases, future minimum payments due		$ 917,130,000
Operating leases, start year		2021
Operating leases, expiration year		2029
Other Leases [Member]
Other Commitments [Line Items]
Operating leases, future minimum payments due		$ 9,893,000
Operating leases, start year		2021
Operating leases, expiration year		2024
12200 TEU Containerships [Member]
Other Commitments [Line Items]
Number of containerships to be build under purchase order | Containership	5
Purchase commitment for aggregate purchase price	$ 419,825,000
Number of payable installments | Installment	4
Purchase commitment for initial payment		$ 41,982,500

Commitments and contingencies_2

Commitments and contingencies - Schedule of Commitment Under Operating Leases (Detail) $ in Millions	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 147.1
2022	143.1
2023	144.6
2024	147.8
2025	125.7
Thereafter	218.7
Operating leases, future minimum payments due	$ 927

Commitments and contingencies_3

Commitments and contingencies - Summary of Outstanding Commitments for Remaining Installment Payments (Detail) $ in Millions	Dec. 31, 2020USD ($)
Purchase Obligation Fiscal Year Maturity [Abstract]
2021	$ 142.7
2022	235.1
Total	$ 377.8

Financial instruments - Additio

Financial instruments - Additional Information (Detail) - USD ($)		Aug. 30, 2019	Dec. 31, 2020	Feb. 29, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Derivative [Line Items]
Carrying value, long-term debt			$ 3,566,100,000		$ 3,060,600,000
Operating lease liabilities, fair value	[1]		828,111,000		940,034,000
Operating lease liabilities			830,200,000		942,308,000	$ 893,300,000	$ 0
Fair value of other financing arrangements excluding deferred financing fees			891,710,000		553,754,000
Carrying value of other financing arrangements excluding deferred financing fees			879,468,000		513,771,000
Long-term debt, gross			$ 3,748,100,000		3,246,400,000
Discount expected to be realized on repatriation of cash			45.00%
Increase five percentage on discount results an increase in fair value			$ 3,330,000
Decrease five percentage on discount results in decrease in fair value			3,330,000
Amount that would be settled in cash in the next 12 months			25,966,000
Derivative asset liability subject to master netting arrangement			0		0
Estimated accumulated other comprehensive loss expected to be reclassified to net earnings			1,094,000
Interest Rate Swaps [Member]
Derivative [Line Items]
Payment for interest rate swap contract termination		$ 97,955,000
Senior Unsecured Notes [Member]
Derivative [Line Items]
Carrying value, long-term debt			80,000,000		80,000,000
Fair value, long-term debt			89,207,000		82,816,000
Aggregate fair value, long-term debt			89,207,000		82,816,000
Long-term debt, gross			80,000,000		80,000,000
2025 Notes and 2026 Notes [Member]
Derivative [Line Items]
Carrying value, long-term debt			369,100,000		349,106,000
Fair value, long-term debt			538,083,000		525,591,000
Aggregate fair value, long-term debt			538,083,000		525,591,000
Long-term debt, gross			500,000,000		500,000,000
2027 Fairfax Notes [Member]
Derivative [Line Items]
Carrying value, long-term debt				$ 100,000,000
Fair value, long-term debt				101,975,000
Aggregate fair value, long-term debt				$ 101,975,000
Exchangeable Notes [Member]
Derivative [Line Items]
Carrying value, long-term debt			195,000,000
Fair value, long-term debt			195,232,000
Aggregate fair value, long-term debt			195,232,000
Long-term debt, gross			201,250,000
Revolving Credit Facilities and Term Loan Credit Facilities [Member]
Derivative [Line Items]
Fair value, long-term debt excluding deferred financing fees			2,827,984,000		2,624,711,000
Carrying value, long-term debt			$ 2,866,850,000		$ 2,666,274,000
[1]	revolving credit facilities and term loan credit facilities

Financial instruments - Schedul

Financial instruments - Schedule of Outstanding Interest Rate Derivatives (Detail)	12 Months Ended
	Dec. 31, 2020USD ($)
5.4200% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	5.42%
Derivative, notional amount	$ 302,300,000
Effective date	Sep. 6, 2007
Ending date	May 31, 2024
5.4200% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 302,300,000
1.6490% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	1.649%
Derivative, notional amount	$ 160,000,000
Effective date	Sep. 27, 2019
Ending date	May 14, 2024
1.6490% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 160,000,000
0.7270% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	0.727%
Derivative, notional amount	$ 125,000,000
Effective date	Mar. 26, 2020
Ending date	Mar. 26, 2025
0.7270% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 125,000,000
0.7800% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	0.78%
Derivative, notional amount	$ 125,000,000
Effective date	Mar. 23, 2020
Ending date	Mar. 23, 2025
0.7800% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 125,000,000
1.6850% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	1.685%
Derivative, notional amount	$ 110,000,000
Effective date	Nov. 14, 2019
Ending date	May 15, 2024
1.6850% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 110,000,000
5.6000% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	5.60%
Derivative, notional amount	$ 93,600,000
Effective date	Jun. 23, 2010
Ending date	Dec. 23, 2021
5.6000% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 93,600,000
1.4900% [Member]
Derivative [Line Items]
Fixed per annum rate swapped for LIBOR	1.49%
Derivative, notional amount	$ 29,400,000
Effective date	Feb. 4, 2020
Ending date	Dec. 30, 2025
1.4900% [Member] | Maximum [Member]
Derivative [Line Items]
Derivative, notional amount	$ 29,400,000

Financial instruments - Summary

Financial instruments - Summary of Financial Instruments Measured at Fair Value (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Contingent consideration asset	$ 90.9
Interest Rate Swaps [Member]
Offsetting Assets [Line Items]
Fair value of derivative liabilities	$ 63	$ 49.3
Derivative Put Instrument [Member]
Offsetting Assets [Line Items]
Fair value of derivative liabilities		$ 0.9

Financial instruments - Sched_2

Financial instruments - Schedule of Gains and Losses Reclassified from Accumulated Other Comprehensive Loss into Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings (losses) recognized in net earnings:
Gain on contingent consideration asset	$ 6.8
Interest Rate Swaps [Member]
Earnings (losses) recognized in net earnings:
Gain loss on fair value	(36.4)	$ (58.8)	$ 14.7
Derivative Put Instrument [Member]
Earnings (losses) recognized in net earnings:
Gain loss on fair value	0.9	23.7	0.8
Interest Expense [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Loss reclassified from AOCL to net earnings
Depreciation and amortization/Interest expense	(0.3)	(0.3)	(0.3)
Depreciation and Amortization [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Loss reclassified from AOCL to net earnings
Depreciation and amortization/Interest expense	$ (1)	$ (0.7)	$ (0.8)

Financial instruments - Sched_3

Financial instruments - Schedule of Gains and Losses Reclassified from Accumulated Other Comprehensive Loss into Earnings (Parenthetical) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cash flows related to settlement of interest rate swaps	$ 21,800,000	$ 126,800,000	$ 41,300,000
Settlement of interest rate swaps, operating activities	(12,900,000)	20,000,000	57,400,000
Interest Rate Swaps [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Cash flows related to settlement of interest rate swaps	$ 21,789,000	$ 126,782,000	41,284,000
Settlement of interest rate swaps, operating activities			$ 41,284,000

Subsequent events - Additional

Subsequent events - Additional Information (Detail)	Jan. 04, 2021USD ($)Vessel$ / shares	Mar. 31, 2021USD ($)Vessel	Feb. 28, 2021USD ($)Vessel	Jan. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Subsequent Event [Line Items]
Dividends on preferred shares					$ 67,100,000	$ 70,400,000	$ 68,700,000
Long-term debt, gross					$ 3,748,100,000	3,246,400,000
Maturity date					Mar. 1, 2027
Senior Unsecured Notes [Member]
Subsequent Event [Line Items]
Long-term debt, gross					$ 80,000,000	$ 80,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 20, 2021
Dividends per common share declared | $ / shares	$ 0.125
Subsequent Event [Member] | High Quality Newbuild Scrubber-fitted Containerships [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel			12
Aggregate purchase price of vessels			$ 806,400,000
Subsequent Event [Member] | Senior Unsecured Notes [Member]
Subsequent Event [Line Items]
Long-term debt, gross			$ 200,000,000
Maturity date			Feb. 29, 2024
Debt instrument, interest rate			6.50%
Subsequent Event [Member] | 11000 TEU Vessel [Member]
Subsequent Event [Line Items]
Repayment upon early termination of sale leaseback financing arrangement				$ 69,166,000
Number of vessel terminated | Vessel	1
Sales-leaseback financing arrangement amount		$ 83,700,000
Subsequent Event [Member] | 24000 TEU Vessels [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel			2
Aggregate purchase price of vessels			$ 287,400,000
Subsequent Event [Member] | 15000 TEU Vessels [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel		6	10
Aggregate purchase price of vessels		$ 697,800,000	$ 1,399,010,000
Option to construct additional number of vessels | Vessel		5	5
Subsequent Event [Member] | 15000 TEU Vessels [Member] | High Quality Newbuild Scrubber-fitted Containerships [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel			4
Option to construct additional number of vessels | Vessel			4
Subsequent Event [Member] | 15000 TEU Vessels [Member] | Young High Quality Scrubber-fitted Containerships [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel			2
Aggregate purchase price of vessels			$ 254,000,000
Subsequent Event [Member] | 12000 TEU Vessels [Member] | High Quality Newbuild Scrubber-fitted Containerships [Member]
Subsequent Event [Line Items]
Number of vessels for construction | Vessel			4
Subsequent Event [Member] | Series D Preferred Shares [Member]
Subsequent Event [Line Items]
Dividends per preferred share declared | $ / shares	$ 0.496875
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 29, 2021
Subsequent Event [Member] | Series E Preferred Shares [Member]
Subsequent Event [Line Items]
Dividends per preferred share declared | $ / shares	$ 0.515625
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 29, 2021
Subsequent Event [Member] | Series G Preferred Shares [Member]
Subsequent Event [Line Items]
Dividends per preferred share declared | $ / shares	$ 0.512500
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 29, 2021
Subsequent Event [Member] | Series H Preferred Shares [Member]
Subsequent Event [Line Items]
Dividends per preferred share declared | $ / shares	$ 0.492188
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 29, 2021
Subsequent Event [Member] | Series I Preferred Stock [Member]
Subsequent Event [Line Items]
Dividends per preferred share declared | $ / shares	$ 0.500000
Dividends declared date	Jan. 4, 2021
Dividends date of record	Jan. 29, 2021
Subsequent Event [Member] | Series D, Series E, Series G and Series H Preferred Share [Member]
Subsequent Event [Line Items]
Dividends on preferred shares	$ 16,763,000