CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
CONSOLIDATED STATEMENTS OF EQUITY
Issuance of shares of common stock upon exercise of stock options	2,000	2,200	2,000	14,700
Purchase of shares of common stock	8,542	261	28,393	73,183
Dividends declared on common stock (dollars per per share)	$ 0.17	$ 0.17	$ 0.51	$ 0.51

Number of share options (or share units) exercised during the current period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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