8. Other Assets

Other assets consist of the following:


	September 30,		December 31,
	2018		2017
Retained interest investments	$	11,388	$	11,147
Accounts receivable, net		7,988		8,460
Notes receivable		3,963		9,522
Prepaid expenses		7,074		6,625
Straight line rent		3,656		3,804
Other assets		5,598		4,637
Accrued interest receivable for Senior Notes held by SPE		935		2,938
Total other assets	$	40,602	$	47,133

Retained Interest Investments

The Company has a beneficial interest in certain bankruptcy-remote qualified SPEs used in the installment sale monetization of certain sales of timberlands in 2007 and 2008. The SPEs’ assets are not available to satisfy the Company’s liabilities or obligations and the liabilities of the SPEs are not the Company’s liabilities or obligations. Therefore, the SPEs’ assets and liabilities are not consolidated in the Company’s condensed consolidated financial statements as of September 30, 2018 and December 31, 2017. The Company’s continuing involvement with the SPEs is the receipt of the net interest payments and the remaining principal of approximately $17.0 million to be received at the end of the installment notes’ fifteen year maturity period, in 2022 through 2024. The Company has a beneficial or retained interest investment related to these SPEs of $11.4 million and $11.1 million as of September 30, 2018 and December 31, 2017, respectively, recorded in other assets on the Company’s condensed consolidated balance sheets.

Accounts Receivable, Net

As of September 30, 2018, accounts receivable, net includes $2.4 million related to estimated lot residuals and certain estimated fees that are recognized as revenue at the time of sale to homebuilders, subject to constraints, and any change in circumstances from the estimated amounts will be updated at each reporting period. The receivable will be collected as the homebuilders build the homes and sell to retail buyers, which can occur over multiple years.

Notes Receivable

Notes receivable consists of the following:


	September 30,		December 31,
	2018		2017
PCR Note, secured by certain assets, 10% interest rate, principal payments due beginning September 2018 per agreed upon schedule, and any remaining amount outstanding is due by December 2020, paid in full February 2018	$	—	$	5,000
Pier Park Community Development District notes, non-interest bearing, due September 2022		803		1,527
Interest bearing homebuilder note, secured by the real estate sold — 5.5% interest rate, principal payment of $0.1 million due February 2019 and any remaining amount outstanding is due by February 2020		1,160		—
Interest bearing homebuilder note, secured by the real estate sold — 5.5% interest rate, principal payment of $0.1 million due September 2018 and any remaining amount outstanding is due by September 2019		809		904
Interest bearing homebuilder note, secured by the real estate sold — 5.5% interest rate, principal payment of $0.1 million due June 2018 and any remaining amount outstanding is due by June 2019		506		857
Interest bearing homebuilder note, secured by the real estate sold — 5.5% interest rate, principal payment of $0.1 million due November 2018 and any remaining amount outstanding is due by November 2019		336		1,060
Interest bearing homebuilder note, secured by the real estate sold — 6.3% interest rate, principal payment of less than $0.1 million due March 2019 and any remaining amount outstanding is due by March 2020		200		—
Various mortgage notes, secured by certain real estate, bearing interest at various rates		149		174
Total notes receivable	$	3,963	$	9,522

The Company evaluates the carrying value of the notes receivable and the need for an allowance for doubtful notes receivable at each reporting date. As of September 30, 2018 and December 31, 2017, there was no allowance for doubtful notes receivable.