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Equity Method Investments, Number Of Joint Ventures With Controlling Interests

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Number of customers deriving the largest portion of revenues.

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Percentage of potential target shares to be earned under Performance Share agreement

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The amount of the cost recognized during the period for defined contribution plans.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Amount of interest capitalized during the period.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

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Business and Summary of Significant Accounting Policies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) customers joint_venture shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Principles of Consolidation and Basis of Presentation:
Number of joint ventures with controlling interests \| joint_venture	2
Accounts Receivable and Deferred Rent Asset:
Number of customers, concentration of credit risk \| customers	4
Functional Currency:
Foreign currency transaction gain (loss), in AOCI and Income Statement	$ (153,900)
Foreign currency transaction gain (loss), reclassified as AOCI	105,000
Foreign currency transaction loss	(48,900)
Property and Equipment:
Labor costs capitalized	47,700	$ 44,700	$ 48,500
Interest costs capitalized	1,500	1,800	2,800
Other Comprehensive Income (Loss):
Accumulated other comprehensive loss	(1,999,332)	(1,836,996)
Revenue Recognition:
Straight line revenue	131,700	155,000	123,700
Rent Expense:
Straight-line ground rent expense	$ 67,800	$ 56,100	$ 38,400
Share-based Compensation:
Shares paid for tax withholding for share based compensation \| shares	1,219,755
Retirement Plan:
Employers percentage of employees first 6 percent	75.00%	75.00%	75.00%
Employee maximum annual contribution eligible for match	6.00%	6.00%	6.00%
Company's contribution	$ 9,100	$ 7,400	$ 6,500
New accounting pronouncement, percent of revenues effected	12.00%
Performance Shares
Share-based Compensation:
Vesting period	3 years
Performance Shares \| 2007 Plan
Share-based Compensation:
Vesting period	3 years
Restricted Stock
Share-based Compensation:
Shares paid for tax withholding for share based compensation \| shares	218,063
Restricted Stock \| 2007 Plan
Share-based Compensation:
Vesting period	4 years
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest
Principles of Consolidation and Basis of Presentation:
Reclassification from accumulated other comprehensive income	$ (9,100)
Foreign Currency Items
Other Comprehensive Income (Loss):
Accumulated other comprehensive loss	$ 2,000,000	$ 1,800,000	$ 800,000
Maximum
Goodwill and Other Intangible Assets:
Estimated useful life of respective assets	20 years
Maximum \| Performance Shares
Share-based Compensation:
Percentage of potential target shares	200.00%
Minimum
Goodwill and Other Intangible Assets:
Estimated useful life of respective assets	3 years
Minimum \| Performance Shares
Share-based Compensation:
Percentage of potential target shares	0.00%
Sales Revenue, Net \| Customer Concentration Risk
Accounts Receivable and Deferred Rent Asset:
Concentration risk, percentage	10.00%	10.00%	10.00%
Uganda \| Corporate Joint Venture
Principles of Consolidation and Basis of Presentation:
Company's ownership percentage	51.00%
Noncontrolling owners, ownership percentage	49.00%
Ghana \| Corporate Joint Venture
Principles of Consolidation and Basis of Presentation:
Company's ownership percentage	51.00%
Noncontrolling owners, ownership percentage	49.00%
South Africa \| Corporate Joint Venture
Principles of Consolidation and Basis of Presentation:
Company's ownership percentage	75.00%
Noncontrolling owners, ownership percentage	25.00%
ATC Europe
Principles of Consolidation and Basis of Presentation:
Noncontrolling owners, ownership percentage	49.00%
Company's ownership percentage	51.00%
ATC, TIPL
Principles of Consolidation and Basis of Presentation:
Company's ownership percentage	51.00%
Other Acquisition 2016
Principles of Consolidation and Basis of Presentation:
Company's ownership percentage	49.00%
Four Customers \| Sales Revenue, Net \| Customer Concentration Risk
Accounts Receivable and Deferred Rent Asset:
Concentration risk, percentage	56.00%