Deferred Sales Commissions, Net (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Components of Deferred Sales Commissions

The components of deferred sales commissions, net for the years ended December 31, 2017 and 2016 were as follows (excluding amounts related to fully amortized deferred sales commissions):

	December 31,
	2017			2016
	(in thousands)
Carrying amount of deferred sales commissions	$	911,852		$	903,252
Less: Accumulated amortization	(597,566		)	(565,681		)
Cumulative CDSC received	(284,160		)	(273,681		)
Deferred sales commissions, net	$	30,126		$	63,890

Expected Amortization of Deferred Sales Commissions

Estimated future amortization expense related to the December 31, 2017 net asset balance, assuming no additional CDSC is received in future periods, is as follows (in thousands):

2018	$	20,778
2019	6,343
2020	2,615
2021	344
2022	38
2023	8
	$	30,126