Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Note [Abstract]

Schedule of Common Stock Outstanding Roll Forward

	Common Stock
	Treasury		Outstanding
Share Activity	(Number of Shares)
Balance at end of 2014	873,374		10,242,405
Issued for stock-based compensation plans	(59,113	)	59,113
Repurchased common stock	80,512		(80,512	)
Balance at end of 2015	894,773		10,221,006
Issued for stock-based compensation plans	(96,619	)	96,619
Repurchased common stock	5,000		(5,000	)
Balance at end of 2016	803,154		10,312,625
Issued for stock-based compensation plans	(27,951	)	27,951
Balance at end of 2017	775,203		10,340,576