Shareholders' Equity (Tables)

9 Months Ended

Sep. 30, 2018

Stockholders' Equity Note [Abstract]

Summary of dividends declared and paid per share

The following table provides a summary of dividends declared and paid per share:

	Nine Months Ended September 30,
	2018				2017
	Declared		Paid		Declared		Paid
Common shares	$	3.020	$	3.000	$	2.960	$	2.940
5.417% Series 1 Cumulative Convertible Preferred shares	$	1.016	$	1.016	$	1.016	$	1.016
5.0% Series C Cumulative Redeemable Preferred shares (1)	$	0.938	$	0.993	$	—	$	—

(1) Amount represents dividends per depository share, each representing 1/1000th of a share.