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Stockholders' Equity and Stock Plans - Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended			36 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Feb. 27, 2020	Jan. 24, 2020	Apr. 23, 2018
Equity [Abstract]
Total number of common shares repurchased (in shares)	203,709	356,000	171,217	730,926
Total purchase price of common shares repurchased (in dollars per share)	$ 7.2	$ 15.0	$ 7.0	$ 29.2
Stock repurchase program, remaining authorized repurchase amount prior to expiration					$ 1.5
Stock repurchase program, authorized amount						$ 25.0	$ 25.0

X

- Definition

Stock Repurchased During Period, Share Price

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- Definition

Amount of stock repurchase plan authorized.

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- Definition

Amount remaining of a stock repurchase plan authorized.

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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