Series B Convertible Preferred Stock and Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Dec. 11, 2019	Nov. 01, 2019	Sep. 18, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsidiary, Sale of Stock [Line Items]
Class of warrant or right, number of securities called by warrants or rights (in shares)	1,500,000
Class of warrant or right, exercise price of warrants or rights (in dollars per share)	$ 12
Proceeds from issuance of preferred stock				$ 95,741	$ 0	$ 0
Temporary equity, carrying amount				93,012	0
Number of shares of common stock sold (in shares)		14,375,000	14,400,000
Public offering price per share			$ 16.00
Net proceeds to NN from the offering			$ 217,300
Series B Convertible Preferred Stock
Subsidiary, Sale of Stock [Line Items]
Temporary equity, liquidation price per share (in dollars per share)	$ 1,000
Proceeds from issuance of preferred stock				$ 95,700
Temporary equity, dividend rate, percentage				10.625%
Temporary equity, increase in dividend rate, percentage				11.625%
Allocation of issuance costs to Preferred Stock				$ 4,259
Temporary equity, carrying amount				93,012	$ 0
Accrual of in-kind dividends				$ 590
Series B Convertible Preferred Stock | Private Placement
Subsidiary, Sale of Stock [Line Items]
Sale of stock, number of shares issued in transaction	100,000
Temporary equity, par value (in dollars per share)	$ 0.01
Sale of stock, price per share (in dollars per share)	$ 1,000