Statements of Stockholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Dividends declared and paid, per share (in dollars per share)	$ 1.10	$ 1.05
Dividends declared but not paid, per share (in dollars per share)	$ 1.10	$ 1.05