Equity Offering - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 01, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity Offering [Abstract]
Number of shares of common stock sold	7,590,000
Public offering price per share	$ 24.00
Net proceeds to NN from the offering	$ 173,100
Repayment of term loan and ABL facilities	$ 148,700	$ 314,313	$ 55,000	$ 401,438