11. LEASES

The Company leases various property and equipment under operating lease arrangements. Lease terms generally range from 3 to 15 years with renewal options for extended terms. Certain leases contain rent escalation clauses that require additional rental payments in the later years of the term. Rent expense for these types of leases is recognized on a straight‑line basis over the minimum lease term. Any lease concessions received by the Company are deferred and recognized as an adjustment to rent expense ratably over the minimum lease term. The Company is required to make additional payments under certain property leases for taxes, insurance and other operating expenses incurred during the operating lease period. Rental expense for the years ended December 31, 2018 and 2017 was $3,654 and $3,378, respectively.

In addition, the Company has entered into capital lease arrangements to finance property and equipment and assumed capital lease obligations in connection with certain acquisitions. The cost basis and accumulated depreciation of assets recorded under capital leases, which are included in property and equipment, are as follows as of December 31, 2018 and 2017:


	December 31,
	2018		2017
Cost	$	4,354	$	2,460
Accumulated depreciation		(951)		(424)
Net book value	$	3,403	$	2,036

Depreciation expense recorded in connection with assets recorded under capital leases was $527 and $295 for the years ended December 31, 2018 and 2017, respectively.

As of December 31, 2018, future minimum lease payments under capital leases and operating leases were as follows:


	Capital		Operating
	Leases		Leases		Total
2019	$	1,057	$	3,524	$	4,581
2020		376		2,784		3,160
2021		252		2,334		2,586
2022		—		2,333		2,333
2023		—		2,213		2,213
2024 and thereafter		—		6,340		6,340
Total	$	1,685	$	19,528	$	21,213
Less—portion representing interest at a weighted average annual rate of 5.0%		(147)
Principal		1,538
Less—current portion		(967)
Capital lease obligations, noncurrent portion	$	571