8. INTANGIBLE ASSETS, NET

Intangible assets, net as of March 31, 2018 and December 31, 2017 consisted of the following (in thousands):

	March 31, 2018		December 31, 2017
Tradenames	$	28,273	$	29,673
Referral relationships, net of accumulated amortization of $7,729 and $7,209, respectively		16,527		16,811
Non-compete agreements, net of accumulated amortization of $4,297 and $4,100, respectively		2,292		2,470
	$	47,092	$	48,954

Tradenames, referral relationships and non-compete agreements are related to the businesses acquired. Typically, the value assigned to tradenames has an indefinite life and is tested at least annually for impairment using the relief from royalty method in conjunction with the Company’s annual goodwill impairment test. The value assigned to referral relationships is being amortized over their respective estimated useful lives which range from six to 16 years. Non-compete agreements are amortized over the respective term of the agreements which range from five to six years.

The following table details the amount of amortization expense recorded for intangible assets for the three months ended March 31, 2018 and 2017 (in thousands):

	Three Months Ended		Three Months Ended
	March 31, 2018		March 31, 2017
Referral relationships	$	520	$	458
Non-compete agreements		197		195
	$	717	$	653

Based on the balance of referral relationships and non-compete agreements as of March 31, 2018, the expected amount to be amortized in 2018 and thereafter by year is as follows (in thousands):

Referral Relationships			Non-Compete Agreements
Years	Annual Amount		Years		Annual Amount
Ending December 31,			Ending December 31,
2018	$	2,068		2018	$	766
2019	$	1,965		2019	$	693
2020	$	1,965		2020	$	481
2021	$	1,965		2021	$	403
2022	$	1,917		2022	$	143
2023	$	1,809		2023	$	3
Thereafter	$	5,358