end of December 2018. Comparatively, in the first nine months of 2018, our cash provided by operating activities was $60.1 million, which was comprised of net earnings of $120.8 million and $39.9 million of non-cash expenses, offset by a $100.5 million seasonal increase in working capital since the end of December 2017. Our investment in working capital declined in 2019 due to opportunistic inventory buying in the fourth quarter of 2018 of products sold in 2019, and lower lumber prices in 2019.
Acquisitions and purchases of property, plant, and equipment comprised most of our cash used in investing activities during the first nine months of 2019 and totaled $38.7 million and $66 million, respectively. Outstanding purchase commitments on existing capital projects totaled approximately $46.1 million on September 28, 2019. We currently plan to spend up to $100 million for the year on capital expenditures. Notable areas of spending include projects to replace our capacity in South Florida resulting from the sale of our Medley facility last year, expand capacity and enhance the productivity of our Deckorators decking product line due to favorable demand trends and share gains we’ve achieved, as well as several projects to expand manufacturing capacity to serve industrial customers and achieve efficiencies through automation. We intend to fund capital expenditures and purchase commitments through our operating cash flows for the balance of the year. The sale and purchase of investments totaling $4.2 million and $6.5 million, respectively, are due to investment activity in our captive insurance subsidiary. Comparatively, acquisitions and purchases of property, plant, and equipment during the first nine months of 2018 totaled $39.0 million and $74.5 million, respectively, and proceeds from the sale of our Medley, FL, plant provided approximately $36 million in net cash proceeds.
Cash flows from financing activities primarily consisted of net repayments under our revolving credit facility of approximately $39.1 million. Additionally, we paid a semi-annual dividend totaling $12.3 million or $0.20 per share.
On September 28, 2019, we had $3.3 million outstanding on our $375 million revolving credit facility, and we had approximately $361.9 million in remaining availability after considering $9.8 million in outstanding letters of credit. Additionally, we have $150 million in availability under an amended “shelf agreement” for long term debt with a current lender after considering the second quarter 2018 issuance of long-term Senior Notes. Financial covenants on the unsecured revolving credit facility and unsecured notes include minimum interest tests and a maximum leverage ratio. The agreements also restrict the amount of additional indebtedness we may incur and the amount of assets which may be sold. We were in compliance with all our covenant requirements on September 28, 2019.
ENVIRONMENTAL CONSIDERATIONS AND REGULATIONS
See Notes to Unaudited Consolidated Condensed Financial Statements, Note E, “Commitments, Contingencies, and Guarantees.”
CRITICAL ACCOUNTING POLICIES
In preparing our consolidated financial statements, we follow accounting principles generally accepted in the United States. These principles require us to make certain estimates and apply judgments that affect our financial position and results of operations. We continually review our accounting policies and financial information disclosures. There have been no material changes in our policies or estimates since December 29, 2018.
On an ongoing basis, we evaluate long-lived assets for indicators of impairment. Although there were no indicators for impairment for any of our reporting units, we continue to monitor the results of the idX reporting unit. They have performed below expectations year-to-date through September; however, management believes the long-term projection for idX is still reasonable and attainable. While the risk of impairment exists, management does not feel an impairment is necessary. Should the Company’s future analysis indicate a significant change in any of the triggering events for this reporting unit, it could result in impairment of the carrying value of goodwill to its implied fair value. There can be no assurance that the Company’s future goodwill impairment testing will not result in a charge to earnings.