Commitments and Contingencies

Leases - We lease office, warehouse and manufacturing space, and certain equipment under non-cancelable operating lease agreements that require us to pay maintenance, insurance, taxes and other expenses in addition to annual rentals. Lease expense under these arrangements was $12.0 million, $10.6 million and $11.3 million in 2017, 2016 and 2015, respectively. Capital lease agreements entered into by us are immaterial. Anticipated future lease costs are based in part on certain assumptions to approximate minimum annual rental commitments at December 31, 2017 under non-cancelable operating leases are as follows:



Year Ending December 31,
2018	$	5,284
2019	$	3,799
2020	$	2,670
2021	$	2,511
2022	$	2,382
Thereafter	$	3,375

Guarantees - We accrue for costs associated with guarantees when it is probable that a liability has been incurred and the amount can be reasonably estimated. The most likely cost to be incurred is accrued based on an evaluation of currently available facts, and where no amount within a range of estimates is more likely, the minimum is accrued. As of December 31, 2017 and 2016, we had no such guarantees.

Litigation - We are subject to various legal proceedings and claims arising in the ordinary course of business, including but not limited to workers' compensation claims, OSHA investigations, employment disputes, service provider disputes, intellectual property disputes, and disputes arising out of alleged defects, breach of contracts, product warranties and environmental matters. Management believes that we maintain adequate insurance or we have established reserves for issues that are probable and estimable in amounts that are adequate to cover reasonable adverse judgments not covered by insurance. Based upon the information available to management and discussions with legal counsel, it is the opinion of management that the ultimate outcome of the various legal actions and claims that are incidental to our business will not have a material adverse impact on the consolidated financial position, results of operations or cash flows; however, such matters are subject to many uncertainties and the outcomes of individual matters are not predictable with assurance.

Warranty - We are subject to warranty claims for products that fail to perform as expected due to design or manufacturing deficiencies. Depending on the terms under which we supply products to our customers, a customer may hold us responsible for some or all of the repair or replacement costs of defective products when the product supplied did not perform as represented. Our policy is to record provisions for estimated future customer warranty costs based on historical trends and for specific claims. These amounts, as they relate to the years ended December 31, 2017 and 2016 are included within accrued liabilities and other in the accompanying Consolidated Balance Sheets. The following presents a summary of the warranty provision for the years ended December 31:



	2017			2016
Balance - Beginning of the year	$	5,552		$	7,580
Provision for new warranty claims	3,461			1,798
Change in provision for preexisting warranty claims	(1,065		)	389
Deduction for payments made	(4,579		)	(3,819		)
Currency translation adjustment	121			(396		)
Balance - End of year	$	3,490		$	5,552

Debt Payments - As disclosed in Note 6, the TLS Agreement requires the Company to repay a fixed amount of principal on a quarterly basis, make mandatory prepayments of excess cash flows, and voluntary prepayments that coincide with certain events.

The following table provides future minimum principal payments due on long-term debt for the next five fiscal years and the remaining years thereafter:



Year Ending December 31,
2018	$	4,375
2019	$	4,375
2020	$	4,375
2021	$	4,375
2022	$	4,375
Thereafter	$	150,938