Consolidated Statements of Equity (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax effect of adoption of new accounting standard	$ (76)	$ 3,492	$ 0
Income tax on stock option exercise and other shares issued to employees and directors	$ 0	$ (267)	$ (323)
Stock option exercises and other shares issued to employees and directors, shares	723	127	138
Dividends declared, per common share (in dollars per share)	$ 0.685	$ 0.665	$ 0.645