Selected Consolidated Financial Statements of Parent, Guarantors and Non-Guarantors - Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 186,778			$ 165,485
Accounts receivable	821,926			846,889
Intercompany receivable	0			0
Prepaid expenses and other	195,189			195,740
Total Current Assets	1,203,893			1,208,114
Property, Plant and Equipment, Net	4,556,719			4,489,557
Other Assets, Net:
Long-term notes receivable from affiliates and intercompany receivable	0			0
Investment in subsidiaries	0			0
Goodwill	4,421,995			4,441,030
Operating lease right-of-use assets (see Note 2.d.)	1,765,496		$ 1,825,721	0
Other	1,629,064			1,718,517
Total Other Assets, Net	7,816,555			6,159,547
Total Assets	13,577,167			11,857,218	$ 11,810,870
Liabilities and Equity
Intercompany Payable	0			0
Debit Balances Under Cash Pools	0			0
Current Portion of Long-Term Debt	394,822			126,406
Total Other Current Liabilities (includes current portion of operating lease liabilities)	1,435,289			1,364,369
Long-Term Debt, Net of Current Portion	8,220,347			8,016,417
Long-Term Operating Lease Liabilities, Net of Current Portion	1,626,907		$ 1,685,771	0
Long-Term Notes Payable to Affiliates and Intercompany Payable	0			0
Other Long-term Liabilities	319,854			417,031
Commitments and Contingencies (See Note 8)
Redeemable Noncontrolling Interests	68,099			70,532
Total Iron Mountain Incorporated Stockholders' Equity	1,510,830			1,861,054
Noncontrolling Interests	1,019			1,409
Total Equity	1,511,849	$ 1,658,981		1,862,463	$ 1,916,024	$ 2,035,874	$ 2,285,134
Total Liabilities and Equity	13,577,167			11,857,218
Eliminations
Current Assets:
Cash and cash equivalents	(133,027)			(67,372)
Accounts receivable	0			0
Intercompany receivable	(456,222)			(821,324)
Prepaid expenses and other	(29)			(29)
Total Current Assets	(589,278)			(888,725)
Property, Plant and Equipment, Net	0			0
Other Assets, Net:
Long-term notes receivable from affiliates and intercompany receivable	(5,180,133)			(4,954,686)
Investment in subsidiaries	(2,992,063)			(2,845,066)
Goodwill	0			0
Operating lease right-of-use assets (see Note 2.d.)	0
Other	0			0
Total Other Assets, Net	(8,172,196)			(7,799,752)
Total Assets	(8,761,474)			(8,688,477)
Liabilities and Equity
Intercompany Payable	(456,222)			(821,324)
Debit Balances Under Cash Pools	(133,027)			(67,372)
Current Portion of Long-Term Debt	(29)			(29)
Total Other Current Liabilities (includes current portion of operating lease liabilities)	0			0
Long-Term Debt, Net of Current Portion	0			0
Long-Term Operating Lease Liabilities, Net of Current Portion	0
Long-Term Notes Payable to Affiliates and Intercompany Payable	(5,180,133)			(4,954,686)
Other Long-term Liabilities	0			0
Commitments and Contingencies (See Note 8)
Redeemable Noncontrolling Interests	0			0
Total Iron Mountain Incorporated Stockholders' Equity	(2,992,063)			(2,845,066)
Noncontrolling Interests	0			0
Total Equity	(2,992,063)			(2,845,066)
Total Liabilities and Equity	(8,761,474)			(8,688,477)
Parent | Reportable legal entities
Current Assets:
Cash and cash equivalents	10			132
Accounts receivable	0			0
Intercompany receivable	0			0
Prepaid expenses and other	0			93
Total Current Assets	10			225
Property, Plant and Equipment, Net	122			190
Other Assets, Net:
Long-term notes receivable from affiliates and intercompany receivable	5,180,133			4,954,686
Investment in subsidiaries	1,940,454			1,862,048
Goodwill	0			0
Operating lease right-of-use assets (see Note 2.d.)	0
Other	1,972			0
Total Other Assets, Net	7,122,559			6,816,734
Total Assets	7,122,691			6,817,149
Liabilities and Equity
Intercompany Payable	167,220			462,927
Debit Balances Under Cash Pools	0			0
Current Portion of Long-Term Debt	0			0
Total Other Current Liabilities (includes current portion of operating lease liabilities)	233,492			268,373
Long-Term Debt, Net of Current Portion	5,199,103			4,223,822
Long-Term Operating Lease Liabilities, Net of Current Portion	0
Long-Term Notes Payable to Affiliates and Intercompany Payable	0			0
Other Long-term Liabilities	12,046			973
Commitments and Contingencies (See Note 8)
Redeemable Noncontrolling Interests	0			0
Total Iron Mountain Incorporated Stockholders' Equity	1,510,830			1,861,054
Noncontrolling Interests	0			0
Total Equity	1,510,830			1,861,054
Total Liabilities and Equity	7,122,691			6,817,149
Guarantors
Current Assets:
Deposits	141,300			58,900
Guarantors | Reportable legal entities
Current Assets:
Cash and cash equivalents	157,771			63,407
Accounts receivable	58,400			47,472
Intercompany receivable	456,222			821,324
Prepaid expenses and other	96,737			109,480
Total Current Assets	769,130			1,041,683
Property, Plant and Equipment, Net	3,049,090			3,010,767
Other Assets, Net:
Long-term notes receivable from affiliates and intercompany receivable	0			0
Investment in subsidiaries	1,051,609			983,018
Goodwill	2,853,466			2,861,381
Operating lease right-of-use assets (see Note 2.d.)	939,631
Other	945,025			982,932
Total Other Assets, Net	5,789,731			4,827,331
Total Assets	9,607,951			8,879,781
Liabilities and Equity
Intercompany Payable	0			0
Debit Balances Under Cash Pools	0			10,612
Current Portion of Long-Term Debt	54,028			63,859
Total Other Current Liabilities (includes current portion of operating lease liabilities)	685,486			618,513
Long-Term Debt, Net of Current Portion	1,457,499			1,878,079
Long-Term Operating Lease Liabilities, Net of Current Portion	871,377
Long-Term Notes Payable to Affiliates and Intercompany Payable	5,180,133			4,954,686
Other Long-term Liabilities	52,842			116,895
Commitments and Contingencies (See Note 8)
Redeemable Noncontrolling Interests	0			0
Total Iron Mountain Incorporated Stockholders' Equity	1,306,586			1,237,137
Noncontrolling Interests	0			0
Total Equity	1,306,586			1,237,137
Total Liabilities and Equity	9,607,951			8,879,781
Non- Guarantors
Current Assets:
Deposits	0			12,700
Non- Guarantors | Reportable legal entities
Current Assets:
Cash and cash equivalents	162,024			169,318
Accounts receivable	763,526			799,417
Intercompany receivable	0			0
Prepaid expenses and other	98,481			86,196
Total Current Assets	1,024,031			1,054,931
Property, Plant and Equipment, Net	1,507,507			1,478,600
Other Assets, Net:
Long-term notes receivable from affiliates and intercompany receivable	0			0
Investment in subsidiaries	0			0
Goodwill	1,568,529			1,579,649
Operating lease right-of-use assets (see Note 2.d.)	825,865
Other	682,067			735,585
Total Other Assets, Net	3,076,461			2,315,234
Total Assets	5,607,999			4,848,765
Liabilities and Equity
Intercompany Payable	289,002			358,397
Debit Balances Under Cash Pools	133,027			56,760
Current Portion of Long-Term Debt	340,823			62,576
Total Other Current Liabilities (includes current portion of operating lease liabilities)	516,311			477,483
Long-Term Debt, Net of Current Portion	1,563,745			1,914,516
Long-Term Operating Lease Liabilities, Net of Current Portion	755,530
Long-Term Notes Payable to Affiliates and Intercompany Payable	0			0
Other Long-term Liabilities	254,966			299,163
Commitments and Contingencies (See Note 8)
Redeemable Noncontrolling Interests	68,099			70,532
Total Iron Mountain Incorporated Stockholders' Equity	1,685,477			1,607,929
Noncontrolling Interests	1,019			1,409
Total Equity	1,686,496			1,609,338
Total Liabilities and Equity	$ 5,607,999			$ 4,848,765