Performance and bid bonds are customarily required for dredging and marine construction projects, as well as some environmental & infrastructure projects. The Company has bonding agreements with Argonaut Insurance Company, Berkley Insurance Company, Chubb Surety and Liberty Mutual Insurance Company under which the Company can obtain performance, bid and payment bonds. The Company also has outstanding bonds with Travelers Casualty and Surety Company of America and Zurich American Insurance Company (“Zurich”). Bid bonds are generally obtained for a percentage of bid value and amounts outstanding typically range from $1,000 to $10,000. At December 31, 2018, the Company had outstanding performance bonds with a notional amount of approximately $1,389,239, of which $78,314 relates to projects from the Company’s historical environmental & infrastructure businesses. The revenue value remaining in backlog related to the projects of continuing operations totaled approximately $619,426.

In connection with the sale of our historical demolition business, the Company was obligated to keep in place the surety bonds on pending demolition projects for the period required under the respective contract for a project and issued Zurich a letter of credit related to this exposure. In February 2017, the Company was notified by Zurich of an alleged default triggered on a historical demolition surety performance bond in the aggregate of approximately $20,000 for failure of the contractor to perform in accordance with the terms of a project. In May 2017, Zurich drew upon the letter of credit in the amount of $20,881. In order to fund the draw on the letter of credit, the Company had to increase the borrowings on its revolving credit facility. As the outstanding letters of credit previously reduced the Company’s availability under the revolving credit facility, the draw down on the Company’s letter of credit does not impact its liquidity or capital availability.

Pursuant to the terms of sale of our historical demolition business, the Company received an indemnification from the buyer for losses resulting from the bonding arrangement. The Company intends to aggressively pursue enforcement of the indemnification provisions if the buyer of the historical demolition business is found to be in default of its obligations. The Company cannot estimate the amount or range of recoveries related to the indemnification or resolution of the Company’s responsibilities under the surety bond. The surety bond claim impact has been included in discontinued operations and is discussed in Note 14, Business Combinations and Dispositions.

Certain foreign projects performed by the Company have warranty periods, typically spanning no more than one to three years beyond project completion, whereby the Company retains responsibility to maintain the project site to certain specifications during the warranty period. Generally, any potential liability of the Company is mitigated by insurance, shared responsibilities with consortium partners, and/or recourse to owner-provided specifications.

As is customary with negotiated contracts and modifications or claims to competitively bid contracts with the federal government, the government has the right to audit the books and records of the Company to ensure compliance with such contracts, modifications, or claims, and the applicable federal laws. The government has the ability to seek a price adjustment based on the results of such audit. Any such audits have not had, and are not expected to have, a material impact on the financial position, operations, or cash flows of the Company.

Various legal actions, claims, assessments and other contingencies arising in the ordinary course of business are pending against the Company and certain of its subsidiaries. These matters are subject to many uncertainties, and it is possible that some of these matters could ultimately be decided, resolved, or settled adversely to the Company. Although the Company is subject to various claims and legal actions that arise in the ordinary course of business, except as described below, the Company is not currently a party to any material legal proceedings or environmental claims. The Company records an accrual when it is probable a liability has been incurred and the amount of loss can be reasonably estimated. The Company does not believe any of these proceedings, individually or in the aggregate, would be expected to have a material effect on results of operations, cash flows or financial condition.

On April 23, 2014, the Company completed the sale of NASDI, LLC (“NASDI”) and Yankee Environmental Services, LLC (“Yankee”), which together comprised the Company’s historical demolition business, to a privately owned demolition company. Under the terms of the divestiture, the Company retained certain pre-closing liabilities relating to the disposed business. Certain of these liabilities and a legal action brought by the Company to enforce the buyer’s obligations under the sale agreement are described below.

On January 14, 2015, the Company and our subsidiary, NASDI Holdings, LLC, brought an action in the Delaware Court of Chancery to enforce the terms of the Company's agreement to sell NASDI and Yankee. Under the terms of the agreement, the Company received cash of $5,309 and retained the right to receive additional proceeds based upon future collections of outstanding accounts receivable and work in process existing at the date of close. The Company seeks specific performance of the buyer’s obligation to collect and to remit the additional proceeds, and other related relief. Defendants have filed counterclaims alleging that the Company misrepresented the quality of its contracts and receivables prior to the sale. The Company denies defendants’ allegations and intends to vigorously defend against the counterclaims.

The Company is in the process of negotiating a Consent Order with the Florida Department of Environmental Protection regarding alleged impacts to a seagrass habitat in connection with a project in Charlotte County, Florida. The Company estimates the range of potential loss related to this matter as between $200,000 and $250,000.

In September 2018, the EPA Region 4 informed the Company of the EPA’s intent to file an administrative complaint against the Company relating to a project the Company performed at PortMiami from 2013-2015, although no complaint has been filed to date, to the Company’s knowledge. The EPA is alleging violations of Section 103 of the Marine Protection, Research, and Sanctuaries Act (“MPRSA”) and failure to report violations of the MPRSA. The Company disagrees with the EPA on whether a violation occurred and, if a violation did occur, the appropriate penalty calculation, and we will defend ourselves vigorously.

Except as noted above, the Company has not accrued any amounts with respect to the above matters as the Company does not believe, based on information currently known to it, that a loss relating to these matters is probable, and an estimate of a range of potential losses relating to these matters cannot reasonably be made.

The Company leases certain operating equipment and office facilities under long-term operating leases expiring at various dates through 2025. The equipment leases contain renewal or purchase options that specify prices at the then fair value upon the expiration of the lease terms. The leases also contain default provisions that are triggered by an acceleration of debt maturity under the terms of the Company’s Credit Agreement, or, in certain instances, cross default to other equipment leases and certain lease arrangements require that the Company maintain certain financial ratios comparable to those required by its Credit Agreement. Additionally, the leases typically contain provisions whereby the Company indemnifies the lessors for the tax treatment attributable to such leases based on the tax rules in place at lease inception. The tax indemnifications do not have a contractual dollar limit. To date, no lessors have asserted any claims against the Company under these tax indemnification provisions.

2019	$	26,554
2020		22,349
2021		18,430
2022		13,552
2023		9,041
Thereafter		8,697
Total minimum operating lease payments	$	98,623

Total rent expense under long-term operating lease arrangements for the years ended December 31, 2018, 2017 and 2016 was $21,160, $26,664 and $20,006, respectively. This excludes expenses for equipment and facilities rented on a short-term, as-needed basis. For more information about charges to rent expense during 2018 related to the Company’s restructuring refer to Note 11, Restructuring Charges.