Commitments

Operating Leases

The Company has entered into non-cancelable operating lease agreements for the rental of office space and equipment. Certain of these leases include options to renew as well as rent escalation clauses and in certain cases, incentives from the landlord for rent-free months and premises reductions, and allowances for tenant improvements. The rent escalations and incentives have been reflected in the table below.

Future minimum lease payments, as of December 31, 2017, associated with these agreements with terms of one year or more are as follows:



Years Ending December 31:	(amounts in thousands)
2018	$	6,700
2019	5,180
2020	4,438
2021	3,993
2022	3,698
Thereafter	8,732
	$	32,741

Total operating lease expense included in selling, general, and administrative expenses was approximately $9.4 million, $8.4 million, and $8.1 million for the years ending December 31, 2017, 2016, and 2015, respectively.

Contingencies

Sales and Other State Non-income Tax Liabilities

The Company's sales and other state non-income tax filings are subject to routine audits by authorities in the jurisdictions where it conducts business in the United States which may result in assessments of additional taxes. The Company accrues sales and other non-income tax liabilities based on the Company's best estimate of its probable liability utilizing currently available information and interpretation of relevant tax regulations. Given the nature of the Company's business, significant subjectivity exists as to both whether sales and other state non-income taxes can be assessed on its activity and how the sales tax will ultimately be measured by the relevant jurisdictions. The Company makes a determination for each reporting period whether the estimates for sales and other non-income taxes in certain states should be revised. Non-income tax expense is included in selling, general and administrative expenses on its consolidated statements of operations and the liability is reflected in sales tax payable within other current liabilities as of December 31, 2017 and 2016, on its consolidated balance sheets.

Legal Proceedings

The Company is subject to legal proceedings and claims that arise in the ordinary course of its business. The Company does not believe the outcome of these other matters will have a material adverse effect on the Company’s business, financial condition, results of operations or cash flows.