AMDOCS LIMITED NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS — (Continued) (dollar and share amounts in thousands, except per share data) These instruments are generally short-term in nature, with typical maturities of less than 12 months, and are subject to fluctuations in foreign exchange rates. The effect of the Company’s derivative instruments not designated as hedging instruments in the consolidated statements of income for the fiscal years ended September 30, 2013, 2012 and 2011, respectively, which partially offsets the foreign currency impact from the underlying exposure, is summarized as follows: Accounts receivable, net consists of the following: Components of equipment and leasehold improvements, net are: Total depreciation expense on equipment and leasehold improvements for fiscal years 2013, 2012 and 2011, was $104,624, $107,470 and $113,910, respectively. Note 8 — Equipment and Leasehold Improvements, Net Note 7 — Accounts Receivable, Net Gains (Losses) Recognized in Income Year Ended September 30, 2013 2012 2011 Line item in statements of income: Revenue .............................................. $ 362 $ (302) $(2,060) Cost of service ......................................... 4,666 (1,548) (1,301) Research and development ............................... 1,136 (319) 151 Selling, general and administrative ......................... 1,276 (518) (254) Interest and other expense, net ............................ 4,145 (1,250) 1,713 Income taxes .......................................... (1,179) 506 (311) Total ................................................... $10,406 $(3,431) $(2,062) As of September 30, 2013 2012 Computer equipment .......................................... $1,020,643 $ 967,381 Leasehold improvements ....................................... 189,655 174,568 Furniture, fixtures and other .................................... 63,158 59,972 1,273,456 1,201,921 Less accumulated depreciation .................................. (997,912) (924,014) $ 275,544 $ 277,907 As of September 30, 2013 2012 Accounts receivable — billed ...................................... $587,928 $573,090 Accounts receivable — unbilled .................................... 110,626 130,697 Less — allowances .............................................. (20,335) (16,564) Accounts receivable, net .......................................... $678,219 $687,223 F-23