DEFERRED CHARGES AND OTHER NON-CURRENT ASSETS

Deferred charges and other non-current assets at December 31, 2012 and 2013 were as follows (in thousands):



	December 31, 2012		December 31, 2013
Prepaid agreements not to compete, net of accumulated amortization of $4,877 and $4,807, respectively	$	326	$	1,299
Deferred loan costs, net of accumulated amortization of $199 and $1,252, respectively	3,041		2,602
Deferred income tax asset	2,220		—
Convertible junior subordinated debenture origination costs, net of accumulated amortization of $1,811 and $1,095, respectively	2,232		2,949
Tradenames	1,605		5,430
Deferred charges and other non-current assets	$	9,424	$	12,280

Agreements not to compete are amortized over the term of the respective agreements, ranging generally from one to ten years. Amortization expense was $104,634, $98,849 and $79,207 for the years ended December 31, 2011, 2012 and 2013, respectively. Deferred loan costs are being amortized over the term of the related debt using the effective interest method. In April 2013, we wrote off approximately $0.4 million of unamortized deferred loan costs in connection with the Third Amendment to our Credit Facility. Our tradenames have indefinite lives and therefore are not amortized.