Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Roll forward of allowance for doubtful accounts and credit memo reserves

Rollforward of allowance for doubtful accounts and credit memo reserves is as follows:

YEAR ENDED DECEMBER 31,	BALANCE AT BEGINNING OF THE YEAR		CREDIT MEMOS CHARGED TO REVENUE		ALLOWANCE FOR BAD DEBTS CHARGED TO EXPENSE		DEDUCTIONS AND OTHER(1)		BALANCE AT END OF THE YEAR
2020	$	42,856	$	55,118	$	34,411	$	(75,404)	$	56,981
2019	43,584		51,846		19,389		(71,963)		42,856
2018	46,648		36,329		18,625		(58,018)		43,584

(1)Primarily consists of the issuance of credit memos, the write-off of accounts receivable and the impact associated with currency translation adjustments.

Components of prepaid expenses

Accrued expenses, with items greater than 5% of total current liabilities are shown separately, and consist of the following:

	DECEMBER 31,
DESCRIPTION	2020		2019
Interest	$	131,448	$	97,987
Sales tax and VAT payable	131,780		115,352
Dividends	187,867		186,021
Operating lease liabilities	250,239		223,249
Other	444,954		339,143
Accrued expenses	$	1,146,288	$	961,752

Property, Plant and Equipment at cost

Property, plant and equipment are stated at cost and depreciated using the straight-line method with the following useful lives (in years):

DESCRIPTION	RANGE
Buildings and building improvements	5 to 40
Leasehold improvements	5 to 10 or life of the lease (whichever is shorter)
Racking	1 to 20 or life of the lease (whichever is shorter)
Warehouse equipment/vehicles	1 to 10
Furniture and fixtures	1 to 10
Computer hardware and software	2 to 5

Property, plant and equipment (including financing leases in the respective category), at cost, consist of the following:

	DECEMBER 31,
DESCRIPTION	2020		2019
Land	$	354,395	$	448,566
Buildings and building improvements	3,040,253		3,029,309
Leasehold improvements	969,273		852,022
Racking	2,083,199		2,040,832
Warehouse equipment/vehicles	499,787		483,218
Furniture and fixtures	52,978		54,275
Computer hardware and software	746,993		689,261
Construction in progress	499,459		451,423
Property, plant and equipment	$	8,246,337	$	8,048,906

Schedule of operating and financing lease right-of-use assets and lease liabilities

Operating and financing lease right-of-use assets and lease liabilities as of December 31, 2020 and 2019 are as follows:

	DECEMBER 31,
DESCRIPTION	2020		2019
Assets:
Operating lease right-of-use assets(1)	$	2,196,502	$	1,869,101
Financing lease right-of-use assets, net of accumulated depreciation(2)(3)	310,534		327,215
Liabilities:
Current
Operating lease liabilities	$	250,239	$	223,249
Financing lease liabilities(3)	43,149		46,582
Long-term
Operating lease liabilities	2,044,598		1,728,686
Financing lease liabilities(3)	323,162		320,600

(1)At December 31, 2020 and 2019, these assets are comprised of approximately 99% real estate related assets (which include land, buildings and racking) and 1% non-real estate related assets (which include warehouse equipment, vehicles, furniture and fixtures and computer hardware and software).

(2)At December 31, 2020, these assets are comprised of approximately 72% real estate related assets and 28% non-real estate related assets. At December 31, 2019, these assets are comprised of approximately 69% real estate related assets and 31% non-real estate related assets.

(3)Financing lease right-of-use assets, current financing lease liabilities and long-term financing lease liabilities are included within Property, Plant and Equipment, Net, Current portion of long-term debt and Long-term Debt, net of current portion, respectively, within our Consolidated Balance Sheets.

Schedule of lease terms and discount rates/Other lease information

The components of the lease expense for the years ended December 31, 2020 and 2019 are as follows:

	YEAR ENDED DECEMBER 31,
DESCRIPTION	2020		2019
Operating lease cost(1)	$	499,464	$	459,619
Financing lease cost:
Depreciation of financing lease right-of-use assets	$	51,629	$	59,258
Interest expense for financing lease liabilities	19,942		21,031

(1)Operating lease cost, the majority of which is included in Cost of sales, includes variable lease costs of $111,501 and $105,922 for the years ended December 31, 2020 and 2019, respectively.

Weighted average remaining lease terms and discount rates as of December 31, 2020 and 2019 are as follows:

	DECEMBER 31, 2020				DECEMBER 31, 2019
	OPERATING LEASES		FINANCING LEASES		OPERATING LEASES		FINANCING LEASES
Remaining Lease Term	11.1 years		11.5 years		11.0 years		11.6 years
Discount Rate	6.9	%	5.9	%	7.1	%	5.7	%

Supplemental cash flow information relating to our leases for the years ended December 31, 2020 and 2019 is as follows:

	YEAR ENDED DECEMBER 31,
CASH PAID FOR AMOUNTS INCLUDED IN MEASUREMENT OF LEASE LIABILITIES:	2020		2019
Operating cash flows used in operating leases	$	360,088	$	338,059
Operating cash flows used in financing leases (interest)	19,942		21,031
Financing cash flows used in financing leases	47,829		58,033
NON-CASH ITEMS:
Operating lease modifications and reassessments	$	143,382	$	108,023
New operating leases (including acquisitions and sale-leaseback transactions)	370,011		170,464

Operating lease maturity table

The estimated minimum future lease payments as of December 31, 2020, are as follows:

YEAR	OPERATING LEASES(1)		SUBLEASE INCOME		FINANCING LEASES(1)
2021	$	380,607	$	(6,208)	$	62,669
2022	362,970		(5,752)		54,499
2023	334,893		(5,222)		45,557
2024	307,039		(3,771)		38,051
2025	281,487		(1,661)		32,261
Thereafter	1,687,706		(6,229)		268,542
Total minimum lease payments	3,354,702		$	(28,843)	501,579
Less amounts representing interest or imputed interest	(1,059,865)				(135,268)
Present value of lease obligations	$	2,294,837			$	366,311

(1)Estimated minimum future lease payments exclude variable common area maintenance charges, insurance and taxes.

Finance lease maturity table

The estimated minimum future lease payments as of December 31, 2020, are as follows:

YEAR	OPERATING LEASES(1)		SUBLEASE INCOME		FINANCING LEASES(1)
2021	$	380,607	$	(6,208)	$	62,669
2022	362,970		(5,752)		54,499
2023	334,893		(5,222)		45,557
2024	307,039		(3,771)		38,051
2025	281,487		(1,661)		32,261
Thereafter	1,687,706		(6,229)		268,542
Total minimum lease payments	3,354,702		$	(28,843)	501,579
Less amounts representing interest or imputed interest	(1,059,865)				(135,268)
Present value of lease obligations	$	2,294,837			$	366,311

(1)Estimated minimum future lease payments exclude variable common area maintenance charges, insurance and taxes.

Schedule of carrying value of goodwill, net for each of the reporting units

The carrying value of goodwill, net for each of our reporting units described above as of December 31, 2019 is as follows:

SEGMENT	REPORTING UNIT	CARRYING VALUE AS OF DECEMBER 31, 2019
Global RIM (as defined in Note 10) Business	North America RIM	$	2,715,550
	Europe RIM	572,482
	Latin America RIM	140,897
	ANZ RIM	274,913
	Asia RIM	239,059
Global Data Center Business	Global Data Center	424,568
Corporate and Other Business	Fine Arts	37,533
	Entertainment Services	34,102
	Technology Escrow Services	46,105
Total		$	4,485,209

The carrying value of goodwill, net for each of our reporting units described above as of December 31, 2020 is as follows:

SEGMENT	REPORTING UNIT	CARRYING VALUE AS OF DECEMBER 31, 2020
Global RIM Business	North America RIM	$	2,719,182
	Europe RIM	641,621
	Latin America RIM	117,834
	ANZ RIM	301,251
	Asia RIM	244,294
Global Data Center Business	Global Data Center	436,987
Corporate and Other Business	Fine Arts	15,176
	Entertainment Services	35,159
	Technology Escrow Services	46,105
Total		$	4,557,609

Schedule of changes in the carrying value of goodwill attributable to each reportable operating segment

The changes in the carrying value of goodwill attributable to each reportable operating segment for the years ended December 31, 2020 and 2019 are as follows:

	GLOBAL RIM BUSINESS		GLOBAL DATA CENTER BUSINESS		CORPORATE AND OTHER BUSINESS		TOTAL CONSOLIDATED
Goodwill balance, net of accumulated amortization, as of December 31, 2018	$	3,899,210	$	425,956	$	115,864	$	4,441,030
Tax deductible goodwill acquired during the year	16,450		—		—		16,450
Non-tax deductible goodwill acquired during the year	11,228		—		1,904		13,132
Fair value and other adjustments	4,439		258		(417)		4,280
Currency effects	11,574		(1,646)		389		10,317
Goodwill balance, net of accumulated amortization, as of December 31, 2019	3,942,901		424,568		117,740		4,485,209
Non-tax deductible goodwill acquired during the year	54,258		—		—		54,258
Goodwill impairment	—		—		(23,000)		(23,000)
Fair value and other adjustments	(3,815)		—		403		(3,412)
Currency effects	30,838		12,419		1,297		44,554
Goodwill balance, net of accumulated amortization, as of December 31, 2020	$	4,024,182	$	436,987	$	96,440	$	4,557,609
Accumulated Goodwill Impairment Balance as of December 31, 2019	$	132,409	$	—	$	3,011	$	135,420
Accumulated Goodwill Impairment Balance as of December 31, 2020	$	132,409	$	—	$	26,011	$	158,420

Components of Gain/Loss on Sale/Disposal of Property, Plant and Equipment

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Consolidated gain on disposal/write-down of property, plant and equipment, net	$	363,537	$	63,824	$	73,622
The gains primarily consisted of:	•Gains associated with sale-leaseback transactions of approximately $342,100, of which (i) approximately $265,600 relates to the sale-leaseback transactions of 14 facilities in the United States during the fourth quarter of 2020 and (ii) approximately $76,400 relates to the sale-leaseback transactions of two facilities in the United States during the third quarter of 2020, each as part of our program to monetize a small portion of our industrial real estate assets. The terms for these leases are consistent with the terms of our lease portfolio, which are disclosed in Note 2.i. •Gains of approximately $24,100 associated with the Frankfurt JV Transaction (as defined in Note 3)		•Gains associated with sale and sale-leaseback transactions of approximately $67,800 in the United States •The sale of certain land and buildings of approximately $36,000 in the United Kingdom Partially offset by losses from: •The impairment charge on the assets associated with the select offerings within our Iron Mountain Iron Cloud ("Iron Cloud") portfolio and loss on the subsequent sale of certain IT infrastructure assets and rights to certain hardware and maintenance contracts used to deliver these Iron Cloud offerings of approximately $25,000. •The write-down of certain property, plant and equipment of approximately $15,700 in the United States.		•Gain on sale of real estate of approximately $63,800 in the United Kingdom •Gains associated with the involuntary conversion of assets included in a facility that we own in Argentina partially destroyed in a fire in 2014, of approximately $8,800 during the fourth quarter of 2018

Schedule of amortization expenses

Amortization expense associated with finite-lived intangible assets, revenue reduction associated with the amortization of Customer Inducements and net revenue reduction associated with the amortization of Data Center Above-Market Leases and Data Center Below-Market Leases for the years ended December 31, 2020, 2019 and 2018 is as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Amortization expense included in depreciation and amortization associated with:
Customer relationship intangible assets	$	117,514	$	117,972	$	113,782
Data center in-place leases and tenant relationships	42,637		46,696		43,061
Third-party commissions asset and other finite-lived intangible assets	7,004		7,957		5,713
Revenue reduction associated with amortization of:
Customer inducements and data center above-market and below-market leases	$	9,878	$	13,703	$	16,281

Estimated amortization expense for existing intangible assets for the next five succeeding fiscal years

Estimated amortization expense for existing finite-lived intangible assets (excluding Contract Fulfillment Costs, as defined and disclosed in Note 2.r.) is as follows:

	ESTIMATED AMORTIZATION
YEAR	INCLUDED IN DEPRECIATION AND AMORTIZATION		REVENUE REDUCTION ASSOCIATED WITH CUSTOMER INDUCEMENTS AND DATA CENTER ABOVE-MARKET AND BELOW-MARKET LEASES
2021	$	168,756	$	7,603
2022	139,983		5,010
2023	135,262		3,084
2024	130,298		1,453
2025	127,771		508
Thereafter	625,052		842

Assets and liabilities carried at fair value measured on a recurring basis

The assets and liabilities carried at fair value and measured on a recurring basis as of December 31, 2020 and 2019, respectively, are as follows:

			FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2020 USING
DESCRIPTION	TOTAL CARRYING VALUE AT DECEMBER 31, 2020		QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)			SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)			SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Money Market Funds(1)	$	62,657	$	—		$	62,657		$	—
Time Deposits(1)	2,121		—			2,121			—
Trading Securities	10,892		10,636		(2)	256		(3)	—
Derivative Liabilities(4)	49,703		—			49,703			—

			FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2019 USING
DESCRIPTION	TOTAL CARRYING VALUE AT DECEMBER 31, 2019		QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)			SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)			SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Money Market Funds(1)	$	13,653	$	—		$	13,653		$	—
Trading Securities	10,732		10,168		(2)	564		(3)	—
Derivative Liabilities(4)	9,756		—			9,756			—

(1)Money market funds and time deposits are measured based on quoted prices for similar assets and/or subsequent transactions.

(2)Certain trading securities are measured at fair value using quoted market prices.

(3)Certain trading securities are measured based on inputs other than quoted market prices that are observable.

(4)Derivative assets and liabilities include (i) interest rate swap agreements, including forward-starting interest rate swap agreements, to limit our exposure to changes in interest rates on a portion of our floating rate indebtedness and (ii) cross-currency swap agreements to hedge the variability of exchange rates impacts between the United States dollar and the Euro and certain of our Euro denominated subsidiaries. Our derivative financial instruments are measured using industry standard valuation models using market-based observable inputs, including interest rate curves, forward and spot prices for currencies and implied volatilities. Credit risk is also factored into the determination of the fair value of our derivative financial instruments. See Note 5 for additional information on our derivative financial instruments.

Schedule of changes in accumulated other comprehensive items, net

The changes in accumulated other comprehensive items, net for the years ended December 31, 2020, 2019 and 2018 are as follows:

	FOREIGN CURRENCY  TRANSLATION AND OTHER ADJUSTMENTS		CHANGE IN FAIR VALUE OF DERIVATIVE INSTRUMENTS		TOTAL
Balance as of December 31, 2017	$	(103,989)	$	—	$	(103,989)
Other comprehensive (loss) income:
Foreign currency translation and other adjustments	(160,702)		—		(160,702)
Change in fair value of derivative instruments	—		(973)		(973)
Total other comprehensive (loss) income	(160,702)		(973)		(161,675)
Balance as of December 31, 2018	(264,691)		(973)		(265,664)
Other comprehensive income (loss):
Foreign currency translation and other adjustments	11,866		—		11,866
Change in fair value of derivative instruments	—		(8,783)		(8,783)
Total other comprehensive income (loss)	11,866		(8,783)		3,083
Balance as of December 31, 2019	(252,825)		(9,756)		(262,581)
Other comprehensive income (loss):
Foreign currency translation and other adjustments	46,635		—		46,635
Change in fair value of derivative instruments	—		(39,947)		(39,947)
Total other comprehensive income (loss)	46,635		(39,947)		6,688
Balance as of December 31, 2020	$	(206,190)	$	(49,703)	$	(255,893)

Schedule of amortization expense associated with software - property, plant and equipment

During the years ended December 31, 2020, 2019 and 2018, capitalized interest is as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Capitalized interest	$	14,321	$	15,980	$	3,732

During the years ended December 31, 2020, 2019 and 2018, capitalized costs associated with the development of internal use computer software projects are as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Capitalized costs associated with the development of internal use computer software projects	$	38,329	$	34,650	$	29,407

Contract Fulfillment Costs, which are included as a component of Other within Other Assets, Net, as of December 31, 2020 and 2019 are as follows:

	DECEMBER 31, 2020						DECEMBER 31, 2019
DESCRIPTION	GROSS CARRYING AMOUNT		ACCUMULATED AMORTIZATION		NET CARRYING AMOUNT		GROSS CARRYING AMOUNT		ACCUMULATED AMORTIZATION		NET CARRY ING AMOUNT
Intake Costs asset	$	63,721	$	(33,352)	$	30,369	$	41,224	$	(23,579)	$	17,645
Commissions asset	91,069		(38,787)		52,282		68,008		(27,178)		40,830

Amortization expense associated with the Intake Costs and Commissions assets for the years ended December 31, 2020, 2019 and 2018 are as follows:

	YEAR ENDED DECEMBER 31,
DESCRIPTION	2020		2019		2018
Intake Costs asset	$	13,300	$	10,144	$	10,380
Commissions asset	24,052		19,109		13,838

Contract with customer, future amortization expense

Estimated amortization expense for Contract Fulfillment Costs is as follows:

YEAR	ESTIMATED AMORTIZATION
2021	$	38,954
2022	24,861
2023	18,836

Schedule of deferred revenue liabilities

Deferred revenue liabilities are reflected as follows in our Consolidated Balance Sheets:

		DECEMBER 31,
DESCRIPTION	LOCATION IN BALANCE SHEET	2020		2019
Deferred revenue - Current	Deferred revenue	$	295,785	$	274,036
Deferred revenue - Long-term	Other Long-term Liabilities	35,612		36,029

Schedule of revenue

Storage rental revenue, including revenue associated with power and connectivity, associated with our Global Data Center Business for the years ended December 31, 2020, 2019 and 2018 are as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Storage rental revenue(1)	$	263,695	$	246,925	$	218,675

(1)Revenue associated with power and connectivity included within storage rental revenue was $47,451, $43,269 and $38,749 for the years ended December 31, 2020, 2019 and 2018, respectively.

Payments to be received

The future minimum lease payments we expect to receive under non-cancellable data center operating leases for which we are the lessor, excluding month to month leases, for the next five years are as follows:

YEAR	FUTURE MINIMUM LEASE PAYMENTS
2021	$	225,554
2022	183,027
2023	142,787
2024	111,106
2025	77,308

Schedule of stock-based compensation expense

Stock-based compensation expense for Employee Stock-Based Awards included in the accompanying Consolidated Statements of Operations for the years ended December 31, 2020, 2019 and 2018 is as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Stock-based compensation expense	$	37,674	$	35,654	$	31,167
Stock-based compensation expense, after tax	36,584		33,103		28,998

Schedule of weighted average assumptions

These values were estimated on the date of grant using the Black-Scholes option pricing model. The weighted average assumptions used for grants in the years ended December 31, 2020, 2019 and 2018 are as follows:

	YEAR ENDED DECEMBER 31,
WEIGHTED AVERAGE ASSUMPTIONS	2020		2019		2018
Expected volatility(1)	25.4	%	24.3	%	25.4	%
Risk-free interest rate(2)	1.45	%	2.47	%	2.65	%
Expected dividend yield(3)	7	%	7	%	7	%
Expected life(4)	10.0 years		5.0 years		5.0 years

(1)Expected volatility is calculated utilizing daily historical volatility over a period that equates to the expected life of the option.

(2)Risk-free interest rate is based on the United States Treasury interest rates whose term is consistent with the expected life (estimated period of time outstanding) of the stock options.

(3)Expected dividend yield is considered in the option pricing model and represents our current annualized expected per share dividends over the current trade price of our common stock.

(4)Expected life of the stock options granted is estimated using the historical exercise behavior of employees.

Summary of stock option activity

A summary of stock option activity for the year ended December 31, 2020 is as follows:

	OPTIONS	WEIGHTED AVERAGE EXERCISE PRICE		WEIGHTED AVERAGE REMAINING CONTRACTUAL TERM (YEARS)	AGGREGATE INTRINSIC VALUE
Outstanding at December 31, 2019	4,835,721	$	35.64
Granted	589,993	33.32
Exercised	(204,540)	24.38
Forfeited	(151,230)	35.36
Expired	(337,425)	35.82
Outstanding at December 31, 2020	4,732,519	$	35.83	6.27	$	469
Options exercisable at December 31, 2020	3,439,748	$	36.40	5.46	$	469
Options expected to vest	1,266,640	$	34.28	8.41	$	—

Summary of restricted stock and RSU activity

The fair value of RSUs vested during the years ended December 31, 2020, 2019 and 2018, are as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Fair value of RSUs vested	$	26,492	$	21,191	$	20,454

A summary of RSU activity for the year ended December 31, 2020 is as follows:

	RSUs	WEIGHTED-AVERAGE GRANT-DATE FAIR VALUE
Non-vested at December 31, 2019	1,203,599	$	34.71
Granted	1,078,124	31.68
Vested	(792,083)	33.45
Forfeited	(195,634)	34.28
Non-vested at December 31, 2020	1,294,006	$	33.02

Schedule of performance stock units and PU activity

The fair value of earned PUs that vested during the years ended December 31, 2020, 2019 and 2018, is as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Fair value of earned PUs that vested	$	11,812	$	6,503	$	3,117

Summary of performance unit (PU) activity

A summary of PU activity for the year ended December 31, 2020 is as follows:

	ORIGINAL PU AWARDS	PU ADJUSTMENT(1)	TOTAL PU AWARDS	WEIGHTED-AVERAGE GRANT-DATE FAIR VALUE
Non-vested at December 31, 2019	1,113,691	(314,798)	798,893	$	36.56
Granted	425,777	—	425,777	34.85
Vested	(316,730)	—	(316,730)	37.29
Forfeited/Performance or Market Conditions Not Achieved	(149,529)	(4,710)	(154,239)	28.28
Non-vested at December 31, 2020	1,073,209	(319,508)	753,701	$	36.98

(1)Represents an increase or decrease in the number of original PUs awarded based on either the final performance criteria or market condition achievement at the end of the performance period of such PUs or a change in estimated awards based on the forecasted performance against the predefined targets.

Other expense (income), net

Consolidated other expense (income), net for the years ended December 31, 2020, 2019 and 2018 consists of the following:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Foreign currency transaction losses (gains), net(1)	$	29,830	$	24,852	$	(15,567)
Debt extinguishment expense	68,300		—		—
Other, net(2)	45,415		9,046		3,875
Other Expense (Income), Net	$	143,545	$	33,898	$	(11,692)

(1)The gain or loss on foreign currency transactions, calculated as the difference between the historical exchange rate and the exchange rate at the applicable measurement date, includes gains or losses primarily related to (i) borrowings in certain foreign currencies under our Revolving Credit Facility (as defined in Note 6), (ii) our previously outstanding Euro Notes (as defined in Note 6), (iii) certain foreign currency denominated intercompany obligations of our foreign subsidiaries to us and between our foreign subsidiaries, which are not considered permanently invested and (iv) amounts that are paid or received on the net settlement amount from forward contracts (as more fully discussed in Note 5).

(2)Other, net for the year ended December 31, 2020 consists primarily of changes in the estimated value of our mandatorily redeemable noncontrolling interests as well as losses on our equity method investments.

Calculation of basic and diluted net income (loss) per share attributable to the entity

The calculation of basic and diluted income (loss) per share for the years ended December 31, 2020, 2019 and 2018 is as follows:

	YEAR ENDED DECEMBER 31,
	2020		2019		2018
Income (loss) from continuing operations	$	343,096	$	268,211	$	367,558
Less: Net income (loss) attributable to noncontrolling interests	403		938		1,198
Income (loss) from continuing operations (utilized in numerator of Earnings Per Share calculation)	342,693		267,273		366,360
Income (loss) from discontinued operations, net of tax	—		104		(12,427)
Net income (loss) attributable to Iron Mountain Incorporated	$	342,693	$	267,377	$	353,933
Weighted-average shares—basic	288,183,000		286,971,000		285,913,000
Effect of dilutive potential stock options	24,903		145,509		234,558
Effect of dilutive potential RSUs and PUs	435,287		570,435		505,030
Weighted-average shares—diluted	288,643,190		287,686,944		286,652,588
Earnings (losses) per share—basic:
Income (loss) from continuing operations	$	1.19	$	0.93	$	1.28
(Loss) income from discontinued operations, net of tax	—		—		(0.04)
Net income (loss) attributable to Iron Mountain Incorporated(1)	$	1.19	$	0.93	$	1.24
Earnings (losses) per share—diluted:
Income (loss) from continuing operations	$	1.19	$	0.93	$	1.28
(Loss) income from discontinued operations, net of tax	—		—		(0.04)
Net income (loss) attributable to Iron Mountain Incorporated(1)	$	1.19	$	0.93	$	1.23
Antidilutive stock options, RSUs and PUs, excluded from the calculation	5,663,981		4,475,745		3,258,078

(1)Columns may not foot due to rounding.

Components of amortizable intangible assets

The gross carrying amount and accumulated amortization of our finite-lived intangible assets as of December 31, 2020 and 2019, respectively, are as follows:

	DECEMBER 31, 2020						DECEMBER 31, 2019
DESCRIPTION	GROSS CARRYING AMOUNT		ACCUMULATED AMORTIZATION		NET CARRYING AMOUNT		GROSS CARRYING AMOUNT		ACCUMULATED AMORTIZATION		NET CARRYING AMOUNT
Assets:
Customer relationship intangible assets(1)	$	1,852,700	$	(668,547)	$	1,184,153	$	1,751,848	$	(544,721)	$	1,207,127
Customer inducements(1)	49,098		(26,923)		22,175		52,718		(29,397)		23,321
Data center lease-based intangible assets(1)(2)	269,988		(149,339)		120,649		265,945		(103,210)		162,735
Third-party commissions asset(3)	34,317		(8,761)		25,556		31,708		(4,134)		27,574
Liabilities:
Data center below-market leases(4)	$	12,854	$	(5,943)	$	6,911	$	12,750	$	(3,937)	$	8,813

(1)Included in Customer relationships, customer inducements and data center lease-based intangibles in the accompanying Consolidated Balance Sheets as of December 31, 2020 and 2019.

(2)Data center lease-based intangible assets includes Data Center In-Place Leases, Data Center Tenant Relationships and Data Center Above-Market Leases.

(3)Included in Other (within Other Assets, Net) in the accompanying Consolidated Balance Sheets as of December 31, 2020 and 2019.

(4)Included in Other long-term liabilities in the accompanying Consolidated Balance Sheets as of December 31, 2020 and 2019.

Schedule of derivative instruments

(Liabilities) assets recognized in our Consolidated Balance Sheets as of December 31, 2020 and 2019 by derivative instrument are as follows:

DERIVATIVE INSTRUMENT(1)	DECEMBER 31, 2020		DECEMBER 31, 2019
Cash Flow Hedges(2)
Interest Rate Swap Agreements	$	(21,062)	$	(8,774)
Net Investment Hedges(3)
August 2023 Cross Currency Swap Agreements	(8,229)		(982)
February 2026 Cross Currency Swap Agreements	(20,412)		—

(1)Our derivative assets are included as a component of Other within Other assets, net and our derivative liabilities are included as a component of Other long-term liabilities in our Consolidated Balance Sheets.

(2)As of December 31, 2020, cumulative net losses of $21,062 are recorded within Accumulated other comprehensive items, net associated with these interest rate swap agreements.

(3)As of December 31, 2020, cumulative net losses of $28,641 are recorded within Accumulated other comprehensive items, net associated with these cross currency swap agreements.