Operating Segments

3 Months Ended

Mar. 31, 2016

Segment Reporting [Abstract]

Segment Reporting Disclosure [Text Block]

During the first quarter of 2016, the Company changed its operating segments to consist of (1) towers and (2) small cells. This change was as a result of growth in small cells from a combination of organic growth, capital expenditures, and acquisitions, as well as the continued progression of the integration of Sunesys, which led to changes in how the Company's chief operating decision maker ("CODM") reviews financial information.

The Company's operating segment change aligns with how the CODM views and evaluates the Company's operations, including how the CODM allocates capital and assesses segment performance. The Company has recast its prior period presentation to conform to its current reporting presentation.

The towers segment provides access, including space or capacity, to the Company's approximately 40,000 towers geographically dispersed throughout the United States. The tower segment also reflects certain network services relating to the Company's towers, consisting of site development services and installation services. The small cells segment provides access, including space or capacity, to the Company's small cell networks designed to facilitate wireless connectivity and supported by 16,500 miles of fiber. To a lesser extent, the small cells segment offers other fiber based solutions, including dark fiber (dedicated fiber strands lit by the customer) and lit fiber (bandwidth provided to the customer using the Company's own optronics).

The measurement of profit or loss used by the CODM to evaluate the results of operations of its operating segments are (1) segment site rental gross margin, (2) segment network services and other gross margin, and (3) segment operating profit. The Company defines segment site rental gross margin as segment site rental revenues less segment site rental cost of operations, which excludes stock-based compensation expense and prepaid lease purchase price adjustments recorded in consolidated cost of operations. The Company defines segment network services and other gross margin as segment network services and other revenues less segment network services and other cost of operations, which excludes stock-based compensation expense recorded in consolidated cost of operations. The Company defines segment operating profit as segment site rental gross margin plus segment network services and other gross margin, less general and administrative expenses attributable to the respective segment.

Costs that are directly attributable to towers and small cells are assigned to those respective segments. The "Other" column (1) represents amounts excluded from specific segments, such as restructuring charges (credits), asset write-down charges, acquisition and integration costs, depreciation, amortization and accretion, amortization of prepaid lease purchase price adjustments, interest expense and amortization of deferred financing costs, gains (losses) on retirement of long-term obligations, net gain (loss) on interest rate swaps, gains (losses) on foreign currency swaps, impairment of available-for-sale securities, interest income, other income (expense), cumulative effect of a change in accounting principle, income (loss) from discontinued operations, and stock-based compensation expense, and (2) reconciles segment operating profit to income (loss) before income taxes, as the amounts are not utilized in assessing each segment’s performance. The "Other" total assets balance includes corporate assets such as cash and cash equivalents which have not been allocated to specific segments. There are no significant revenues resulting from transactions between the Company's operating segments.

	Three Months Ended March 31, 2016									Three Months Ended March 31, 2015
	Towers		Small Cells		Other			Consolidated Total		Towers		Small Cells		Other			Consolidated Total
Segment site rental revenues	$	702,840	$	96,454				$	799,294	$	674,907	$	56,473				$	731,380
Segment network services and other revenues	125,010		10,080					135,090		156,385		12,706					169,091
Segment revenues	827,850		106,534					934,384		831,292		69,179					900,471
Segment site rental cost of operations (a)	204,565		37,483					242,048		204,633		20,513					225,146
Segment network services and other cost of operations (a)	69,989		8,035					78,024		76,191		9,454					85,645
Segment cost of operations (a)	274,554		45,518					320,072		280,824		29,967					310,791
Segment site rental gross margin	498,275		58,971					557,246		470,274		35,960					506,234
Segment network services and other gross margin	55,021		2,045					57,066		80,194		3,252					83,446
Segment general and administrative expenses (a)	23,599		15,522		36,071			75,192		22,722		7,560		30,098			60,380
Segment operating profit	529,697		45,494		(36,071		)	539,120		527,746		31,652		(30,098		)	529,300
Stock-based compensation expense					$	30,705		30,705						$	16,841		16,841
Depreciation, amortization and accretion					277,875			277,875						251,806			251,806
Interest expense and amortization of deferred financing costs					126,378			126,378						134,439			134,439
Other expenses to reconcile to income (loss) from continuing operations before income taxes					52,450			52,450						15,915			15,915
Income (loss) from continuing operations before income taxes								$	51,712								$	110,299
Capital expenditures	$	111,041	$	80,153	$	2,295		$	193,489	$	133,133	$	62,903	$	5,617		$	201,653
Total assets (at period end)	$	18,090,100	$	3,188,474	$	439,677		$	21,718,251	$	18,234,547	$	2,238,790	$	526,493		$	20,999,830

(a) Segment cost of operations exclude (1) stock-based compensation expense of $8.3 million and $3.2 million for the three months ended March 31, 2016 and 2015, respectively and (2) prepaid lease purchase price adjustments of $5.2 million for each of the three months ended March 31, 2016 and 2015. Segment general and administrative expenses exclude stock-based compensation expense of $22.4 million and $13.7 million for the three months ended March 31, 2016 and 2015, respectively.