Concentration of Credit Risk - Summary of Significant Customers and Percentage of Total Revenue for Specified Time Periods Derived from Such Customers (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Site Total Revenue [Member] | Sprint [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	21.20%	19.80%	20.40%
Site Total Revenue [Member] | AT&T [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	20.40%	23.80%	23.90%
Site Total Revenue [Member] | T-Mobile [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	12.70%	10.70%	11.60%
Site Total Revenue [Member] | Verizon Wireless [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	12.70%	14.80%	14.80%
Site leasing [Member] | Sprint [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	23.80%	22.30%	23.60%
Site leasing [Member] | AT&T [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	22.90%	26.80%	28.00%
Site leasing [Member] | T-Mobile [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	13.60%	11.20%	11.70%
Site leasing [Member] | Verizon Wireless [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	13.20%	15.50%	15.40%
Site development [Member] | T-Mobile [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	5.80%	7.00%	10.60%
Site development [Member] | Verizon Wireless [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	8.90%	9.50%	11.20%
Site development [Member] | Ericsson, Inc. [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	24.50%	9.00%	3.00%
Site development [Member] | Nsoro Mastec, LLC [Member]
Concentration Risk [Line Items]
Concentration risk percentage of revenue	16.20%	35.60%	31.20%