Consolidated Statements of Stockholders' Equity (unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Consolidated Statements of Stockholders' Equity (unaudited) [Abstract]
Cash dividends - per share (in dollars per share)	$ 0.54	$ 0.52
Purchase of treasury shares (in shares)	263,507
Net issuance of shares to employee benefit plans and other stock plans (in shares)	54,341	66,920