LEASES

We have operating lease commitments for office and terminal properties, revenue equipment, and computer and office equipment, and we have capital lease commitments for revenue equipment, in each case excluding owner/operator rentals and month-to-month equipment rentals, summarized for the following fiscal years (in thousands):

	Operating		Capital
2017	$	7,135	$	3,062
2018		6,047		3,062
2019		3,844		3,062
2020		430		5,284
2021		-		6,508
Thereafter		-		3,548
Total minimum lease payments	$	17,456	$	24,526
Less: amount representing interest				(2,324	)
Present value of minimum lease payments				22,202
Less: current portion				(2,441	)
Capital lease obligations, long-term			$	19,761

A portion of our operating leases of tractors and trailers contain residual value guarantees under which we guarantee a certain minimum cash value payment to the leasing company at the expiration of the lease. We estimate that the undiscounted value of the residual guarantees is approximately

4.0

million at

December

31,

2016

and

2015,

respectively. The residual guarantees at

December

31,

2016

expire between

August

2018

and

February

2019.

We expect our residual guarantees to approximate the market value at the end of the lease term. Additionally, certain leases contain cross-default provisions with other financing agreements and additional charges if the unit's mileage exceeds certain thresholds defined in the lease agreement.

Rental expense is summarized as follows for each of the

three

years ended

December

31:

(in thousands)	2016		2015		2014
Revenue equipment rentals	$	10,773	$	12,611	$	20,935
Building and lot rentals		708		2,078		3,561
Other equipment rentals		254		340		317
	$	11,735	$	15,029	$	24,813