Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Minimum age required to be eligible to participate in the 401(k) plan	21 years
Expenses accrued relating to employer matching contributions	$ 2,379	$ 2,264	$ 1,971