Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Summary of the Change in the Company's Outstanding Shares of Common Stock

	Year Ended December 31,
	2018			2017			2016
	(In thousands)
Outstanding shares of voting common stock at the beginning of year		37,621			37,544			37,409
Exercise of stock options		121			262			181
Issuance of restricted stock, net of shares withheld for    withholding tax payments and cancellations		22			39			104
Repurchases		(124	)		(224	)		(150	)
Outstanding shares of voting common stock at the end of year		37,640			37,621			37,544