Commitments and Contingencies

Operating Lease Commitments

The Company leases its facilities under non-cancelable operating leases. These operating leases expire at various dates through December 2034 and generally require the payment of real estate taxes, insurance, maintenance and operating costs.

The minimum aggregate future obligations under non-cancelable leases as of December 31, 2017 were as follows (in thousands):



2018	$	50,187
2019	49,418
2020	61,031
2021	58,680
2022	56,211
Thereafter	481,471
Total	$	756,998

Rent expense for the years ended December 31, 2017, 2016 and 2015 was $58.8 million, $50.3 million and $47.9 million, respectively. The Company has entered into sublease agreements with tenants of various properties previously vacated by the Company. The amounts paid to the Company by these sublease tenants was $3.6 million, $1.3 million and $3.6 million for the years ended December 31, 2017, 2016 and 2015, respectively.

As of December 31, 2017, the Company had outstanding letters of credit in the amount of $6.4 million, primarily related to operating leases. The letters of credit remain in effect until the Company fulfills its obligations under these leases or as such obligations expire under the terms of the letters of credit.

Purchase Commitments

As of December 31, 2017, the Company had long-term commitments for bandwidth usage and co-location with various networks and ISPs and for asset purchases for network equipment. Additionally, as of December 31, 2017, the Company had entered into purchase orders with various vendors. The minimum future commitments as of December 31, 2017 were as follows (in thousands):



	Bandwidth and Co-location Commitments		Purchase Order Commitments
2018	$	108,988	$	93,385
2019	27,304		6,175
2020	817		3,205
2021	—		1,385
2022	—		1,190
Thereafter	—		—
Total	$	137,109	$	105,340

Legal Matters

The Company is party to various litigation matters that management considers routine and incidental to its business. Management does not expect the results of any of these routine actions to have a material effect on the Company’s business, results of operations, financial condition or cash flows.

In July 2016, as part of the resolution of a patent infringement lawsuit filed by the Company against Limelight Networks, Inc. (“Limelight”) in 2006, the Company entered into an agreement that requires Limelight to pay the Company $54.0 million in 12 equal installments over three years, beginning in August 2016. During the years ended December 31, 2017 and 2016, the Company received $18.0 million and $9.0 million, respectively, under this agreement, of which $16.4 million and $8.6 million was recorded as a gain contingency, which reduced general and administrative expenses in the consolidated statements of income, respectively, and $1.6 million and $0.4 million was recorded as interest income, respectively.

In November 2015, Limelight filed a complaint in the U.S. District Court for the Eastern District of Virginia against the Company and XO Communications LLC (“XO”), alleging patent infringement by the two companies. The complaint seeks to recover from the Company and XO monetary damages based upon lost revenue due to infringing technology used by the companies. The Company has agreed to indemnify XO for damages it incurs in this matter. The Company has made counterclaims in the action against Limelight alleging that Limelight has infringed multiple of the Company’s content delivery patents, and the Company is seeking monetary damages based upon lost revenue due to the infringing technology used by Limelight. A trial date on Limelight's patents has been set for April 2018. No provision with respect to this matter has been made in the Company’s consolidated financial statements. An estimate of the possible loss or range of loss cannot be made.

Indemnification

The Company enters into standard indemnification agreements in the ordinary course of business. Pursuant to these agreements, the Company agrees to indemnify, hold harmless and reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally the Company's business partners, vendors or customers, in connection with its provision of its services. Generally, these obligations are limited to claims relating to infringement of a patent, copyright or other intellectual property right or the Company’s negligence, willful misconduct or violation of law. Subject to applicable statutes of limitation, the term of each of these indemnification agreements is generally perpetual from the time of execution of the agreement. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is unlimited; however, the Company carries insurance that covers certain third-party claims relating to its services and activities and that could limit the Company’s exposure in that respect.

The Company has agreed to indemnify each of its officers and directors during his or her lifetime for certain events or occurrences that happen by reason of the fact that the officer or director is or was or has agreed to serve as an officer or director of the Company. The Company has director and officer insurance policies that may limit its exposure and may enable the Company to recover a portion of certain future amounts paid.

To date, the Company has not encountered material costs as a result of such indemnification obligations and has not accrued any related liabilities in its financial statements. In assessing whether to establish an accrual, the Company considers such factors as the degree of probability of an unfavorable outcome and the ability to make a reasonable estimate of the amount of loss.