Consolidated Statements of Equity (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends declared, per common share (in dollars per share)	$ 0.6650	$ 0.6450	$ 0.6250
Additional Paid-in Capital
Income tax on stock option exercise and other shares issued to employees and directors	$ (267)	$ (323)	$ 458
Stock option exercises and other shares issued to employees and directors, shares	127	138	196
Retained Earnings
Tax effect of adoption of new accounting standard	$ 3,492
Dividends declared, per common share (in dollars per share)	$ 0.665	$ 0.645	$ 0.6250