Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Cash surrender value of corporate-owned life insurance policies	$ 3,919		$ 3,596
Deferred commissions	16,141		15,530
Restricted cash	659		661
Operating lease assets	11,659
Prepaid expenses, deposits and other	3,378		3,212
Total other long-term assets	$ 35,756	$ 35,482	$ 22,999