Operating Leases

Tenant Contracts

The following table is a summary of the rental cash payments owed to the Company, as a lessor, by tenants pursuant to contractual agreements in effect as of December 31, 2013. Generally, the Company's contracts with its tenants provide for (1) annual escalations, (2) multiple renewal periods at the tenant's option, and (3) only limited termination rights at the applicable tenant's option through the current term. As of December 31, 2013, the weighted-average remaining term of tenant contracts is approximately eight years, exclusive of renewals at the tenant's option. The tenants' rental payments included in the table below are through the current terms with a maximum current term of 20 years and do not assume exercise of tenant renewal options.



	Years Ending December 31,
	2014		2015		2016		2017		2018		Thereafter		Total
Tenant leases	$	2,474,529	$	2,432,301	$	2,342,749	$	2,256,108	$	2,155,880	$	10,419,970	$	22,081,537

Operating Leases

The following table is a summary of rental cash payments owed by the Company, as lessee, to landlords pursuant to contractual agreements in effect as of December 31, 2013. The Company is obligated under non-cancelable operating contracts for land interests under 82% of its towers. The majority of these lease agreements have (1) certain termination rights that provide for cancellation after a notice period, (2) multiple renewal options at the Company's option, and (3) annual escalations. Lease agreements may also contain provisions for a contingent payment based on revenues or the gross margin derived from the wireless infrastructure located on the leased land interest. Approximately three-fourths and nine-tenths of the Company's site rental gross margins for the year ended December 31, 2013 are derived from towers where the land interest under the tower is owned or leased with final expiration dates of greater than 20 years and ten years, respectively, inclusive of renewals at the Company's option. The operating lease payments included in the table below include payments for certain renewal periods at the Company's option up to the estimated wireless infrastructure useful life of 20 years and an estimate of contingent payments based on revenues and gross margins derived from existing tenant leases.



	Years Ending December 31,
	2014		2015		2016		2017		2018		Thereafter		Total
Operating leases	$	565,587	$	573,059	$	578,551	$	582,231	$	583,775	$	7,546,074	$	10,429,277

Rental expense from operating leases was $513.6 million, $372.3 million, and $338.3 million, respectively, for the years ended December 31, 2013, 2012, and 2011. The rental expense was inclusive of contingent payments based on revenues or gross margin derived from the wireless infrastructure located on the leased land interests of $73.7 million, $57.6 million, and $56.4 million, respectively, for the years ended December 31, 2013, 2012, and 2011.