CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - Unaudited (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders' Equity Attributable to Parent
Common dividends declared - per share (in dollars per share)	$ 0.72	$ 0.64
Issuance of shares of common stock, common stock offering, net of expenses	232,205	179,501
Issuance of shares of common stock, dividend reinvestment plan	571	667
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	28,955	23,824