OTHER ASSETS

Other assets at March 31, 2014 and December 31, 2013 consisted of the following (in thousands):



	March 31, 2014		December 31, 2013
Deferred debt issuance costs	$	15,119	$	16,465
Security deposits	10,611		10,617
Other	7,693		6,432
Total	$	33,423	$	33,514

Deferred debt issuance costs arose from (i) the $1.0 billion aggregate principal amount of 1.0% Convertible Senior Notes, due March 15, 2018, issued in March 2012; (ii) a $1.0 billion revolving credit facility entered into in October 2011; (iii) the Company's issuance, in March 2010, of the $575.0 million aggregate principal amount of 1.25% Convertible Senior Notes, due March 15, 2015, and (iv) the $1.0 billion aggregate principal amount of 0.35% Convertible Senior Notes, due June 15, 2020, issued in May 2013. Deferred debt issuance costs are being amortized using the effective interest rate method and the period of amortization was determined at inception of the related debt agreements based upon the stated maturity dates. Unamortized debt issuance costs written off to interest expense in the three months ended March 31, 2014 related to early conversion of convertible debt amounted to $0.3 million. Security deposits principally relate to the Company's leased office spaces.