Other Assets and Accrued Liabilities

Prepaid expenses and other, classified as current assets, included the following:



(in thousands)	June 30, 2018		December 31, 2017
Prepaid rent	$	9,929	$	10,519
Prepaid maintenance expenses	3,806		3,062
Interest rate swaps	4,577		2,411
Deferred contract costs	37,947		—
Other	7,904		1,119
Prepaid expenses and other	$	64,163	$	17,111

Deferred contract and other costs include amounts reimbursed to Sprint for commissions and device costs, and commissions and installation costs in the Company’s Cable and Wireline segments. The deferred contract and other costs increased due to the adoption of Topic 606. Refer to Note 2, Revenue from Contracts with Customers, for additional information.

Deferred charges and other assets, classified as long-term assets, included the following:



(in thousands)	June 30, 2018		December 31, 2017
Interest rate swaps	$	13,925	$	10,776
Deferred contract costs	15,953		—
Other	4,143		2,914
Deferred charges and other assets, net	$	34,021	$	13,690

Accrued liabilities and other, classified as current liabilities, included the following:



(in thousands)	June 30, 2018		December 31, 2017
Sales and property taxes payable	$	4,805	$	3,872
Severance accrual	13		1,028
Asset retirement obligations	641		492
Accrued programming costs	2,934		2,805
Other current liabilities	9,693		5,717
Accrued liabilities and other	$	18,086	$	13,914

Other liabilities, classified as long-term liabilities, included the following:



(in thousands)	June 30, 2018		December 31, 2017
Non-current portion of deferred revenues	$	12,782	$	14,030
Other	2,298		1,263
Other liabilities	$	15,080	$	15,293

The Company's asset retirement obligations are included in the balance sheet captions "Asset retirement obligations" and "Accrued liabilities and other". The Company records the fair value of an asset retirement obligation as a liability in the period in which it incurs a legal obligation associated with the retirement and removal of leasehold improvements or equipment. The Company also records a corresponding asset, which is depreciated over the life of the leasehold improvement or equipment. Subsequent to the initial measurement of the asset retirement obligation, the obligation is adjusted at the end of each period to reflect the passage of time and changes in the estimated future cash flows underlying the obligation. The terms associated with its operating leases, and applicable zoning ordinances of certain jurisdictions, define the Company’s obligations which are estimated and vary based on the size of the towers.