The Company leases office space, service facility centers and equipment under non-cancelable capital and operating lease arrangements. The Company periodically enters into capital leases to finance the purchase of ambulatory infusion pumps. The pumps are capitalized into medical equipment in rental service at their fair market value, which equals the value of the future minimum lease payments and are depreciated over the useful life of the pumps. The weighted average interest rate under capital leases was 3.6% as of September 30, 2017. The leases for office space and service facility centers used in the Company’s logistics operations are operating leases. In most cases, the Company expects its facility leases will be renewed or replaced by other leases in the ordinary course of business.

Future minimum rental payments pursuant to leases that have an initial or remaining non-cancelable lease term in excess of one year as of September 30, 2017 are as follows (in thousands):

At September 30, 2017 and December 31, 2016, pump assets obtained under capital leases had an original cost of approximately $14.0 million and $13.9 million, respectively, and accumulated depreciation of $5.3 million and $3.9 million, respectively.

The Company had minimum future operating lease commitments, mainly related to its leased facilities. Related rental expense for facilities and other equipment from third parties under operating leases for the three and nine months ended September 30, 2017 was $0.2 million and $0.7 million, respectively, compared to $0.3 million and $0.8 million for the same three and nine months ended September 30, 2016.