Leases

The Company has non-cancelable operating leases, primarily for land, tower space, office-space, certain office equipment and vehicles. The operating leases generally contain renewal options for periods ranging from one to ten years and require the Company to pay all executory costs such as maintenance and insurance. Rental expense for operating leases was approximately $23.6 million, $25.2 million, and $27.9 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Future minimum payments under non-cancelable operating leases (with initial or remaining lease terms in excess of one year), future minimum sublease income to be received and a lease commitment under a sale leaseback agreement as of December 31, 2017 are as follows (in thousands):



Year Ending December 31:	Future Minimum Rent Under Operating Leases		Future Minimum Sublease Income			Future Minimum Commitments Under Sale Leaseback Agreement		Net Commitments
2018	$	23,768	$	(1,028	)	$	1,153	$	23,893
2019	20,596		(1,028		)	1,193		20,761
2020	16,373		(1,028		)			15,345
2021	13,028		(1,028		)			12,000
2022	11,869		(1,028		)			10,841
Thereafter	31,596		(1,285		)			30,311
	$	117,230	$	(6,425	)	$	2,346	$	113,151