Acquisitions and Other Transactions (Narrative) (Details) BRL in Millions											3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2015 USD ($) property_interest communications_site		Sep. 30, 2015 BRL	Jul. 01, 2015 USD ($) site	Apr. 29, 2015 USD ($) communications_site	Apr. 29, 2015 BRL communications_site	Mar. 27, 2015 USD ($) communications_site site renewal_period	Nov. 19, 2014 USD ($) property_interest tower	Apr. 03, 2014 USD ($) property_interest communications_site	Sep. 30, 2015 USD ($) property_interest communications_site		Sep. 30, 2015 USD ($) property_interest communications_site		Dec. 31, 2014 USD ($) property_interest communications_site		Sep. 30, 2015 BRL property_interest communications_site	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Pro forma information, revenue of acquiree since acquisition date, actual											$ 172,800,000		$ 289,100,000
Pro forma information gross margin of acquiree since acquisition date actual											76,800,000		$ 132,900,000
Estimated useful lives													11 years
Acquisition-related contingent consideration		$ 18,488,000	[1]								18,488,000	[1]	$ 18,488,000	[1]	$ 28,524,000			$ 24,867,000	$ 27,424,000	$ 31,025,000	$ 31,890,000
Value added tax and other consumption tax receivables		20,727,000									20,727,000		20,727,000		23,228,000	[2]
Contingent consideration arrangements, low range of outcomes		0									0		$ 0
Customer Relationships | Maximum
Business Acquisition [Line Items]
Estimated useful lives													20 years
Customer Relationships | Maximum | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Estimated useful lives													20 years
Acquired Network Location | Maximum
Business Acquisition [Line Items]
Estimated useful lives													20 years
Acquired Network Location | Maximum | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Estimated useful lives													20 years
Verizon Transaction
Business Acquisition [Line Items]
Number of sites acquired | site								11,448
Aggregate purchase price								$ 5,053,000,000
Transaction costs		9,900,000						9,900,000			9,900,000		$ 9,900,000
Transaction costs paid		$ 5,600,000									$ 5,600,000		$ 5,600,000
Verizon Transaction | Leased Sites
Business Acquisition [Line Items]
Aggregate purchase price								$ 4,964,000,000
Number of units leased | communications_site								11,285
Right to lease, weighted average term								28 years
Initial lease term								10 years
Successive terms to renew lease | renewal_period								8
Operating lease, renewal term								5 years
Future monthly sublease rent per tower								$ 1,900
Fixed annual rent escalation percentage								2.00%
Verizon Transaction | Owned Sites
Business Acquisition [Line Items]
Number of sites acquired | communications_site		163						163			163		163				163
Aggregate purchase price								$ 99,000,000
TIM Acquisition
Business Acquisition [Line Items]
Number of sites acquired | communications_site		1,125				4,176	4,176				1,125		1,125				1,125
Aggregate purchase price		$ 130,900,000		BRL 516.9		$ 644,300,000	BRL 1,900.0
Letters of credit, undrawn amount		$ 12,000,000									$ 12,000,000		$ 12,000,000				BRL 47.8
TIM Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													775,216,000
Assumption of existing indebtedness at historical cost													$ 0
Other International Acquisitions 2015
Business Acquisition [Line Items]
Number of sites acquired | communications_site		399									399		399				399
Aggregate purchase price													$ 16,200,000
Other International Acquisitions 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													16,168,000
Assumption of existing indebtedness at historical cost													$ 0
Other Us Acquisition 2015
Business Acquisition [Line Items]
Number of sites acquired | communications_site		199									199		199				199
Aggregate purchase price													$ 128,700,000
Number of property interests acquired | property_interest		3									3		3				3
Acquisition-related contingent consideration		$ 1,300,000									$ 1,300,000		$ 1,300,000
Other Us Acquisition 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													128,723,000
Assumption of existing indebtedness at historical cost													0
BR Towers
Business Acquisition [Line Items]
Number of sites acquired | tower									2,504
Aggregate purchase price									$ 568,900,000				558,700,000
Letters of credit, undrawn amount		$ 82,600,000									$ 82,600,000		82,600,000
Number of property interests acquired | property_interest									4
Additional sites to be acquired | tower									2,113
Right to use, property interests acquired | property_interest									43
Payments for repurchase of trust preferred securities									$ 61,100,000
Assumption of existing indebtedness at historical cost									261,100,000
Value of liabilities assumed									$ 11,500,000
BR Towers | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															568,890,000
Assumption of existing indebtedness at historical cost	[3]														261,136,000
Richland Acquisition
Business Acquisition [Line Items]
Number of sites acquired | communications_site										59
Aggregate purchase price										$ 189,400,000			$ 188,900,000
Number of property interests acquired | property_interest										4
Assumption of existing indebtedness at historical cost										$ 196,500,000
Liabilities, fair value adjustment										$ 5,500,000
Richland Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															189,379,000
Assumption of existing indebtedness at historical cost	[3]														$ 201,999,000
Other International Acquisitions 2014
Business Acquisition [Line Items]
Number of sites acquired | communications_site															159
Aggregate purchase price															$ 28,300,000
Value added tax and other consumption tax receivables															$ 1,200,000
Other International Acquisitions 2014 | Mexico
Business Acquisition [Line Items]
Number of sites acquired | communications_site															299
Aggregate purchase price															$ 40,300,000
Assumption of existing indebtedness at historical cost															3,400,000
Value added tax and other consumption tax receivables															5,600,000
Consideration transferred, other															36,300,000
Partial cash consideration transferred															$ 4,000,000
Other US Acquisition 2014
Business Acquisition [Line Items]
Number of sites acquired | communications_site															184
Aggregate purchase price															$ 180,800,000
Number of property interests acquired | property_interest															6
Acquisition-related contingent consideration															$ 6,300,000
Other US Acquisition 2014 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															180,822,000
Assumption of existing indebtedness at historical cost	[3]														$ 0
Airtel Acquisition
Business Acquisition [Line Items]
Number of sites acquired		1			4,699						1		1				1
Aggregate purchase price					$ 1,109,000,000
Payments to acquire business											$ 806,500,000
Airtel Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													$ 1,108,651,000
Assumption of existing indebtedness at historical cost													$ 0

[1] Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015.

[2] December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments

[3] Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Assumed Richland debt included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million. The fair value adjustments were based primarily on reported market values using Level 2 inputs.