Equity Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Feb. 01, 2020	Aug. 14, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity, Class of Treasury Stock [Line Items]
Common stock cash dividends declared per share (in $ per share)		$ 0.67	$ 0.67	$ 0.55	$ 1.77	$ 1.45
Preferred stock cash dividends declared per share (in $ per share)		$ 1.8125	$ 1.81	$ 1.81	$ 5.44	$ 5.44
Repurchases of common shares (in shares)			70,949		286,620
Weighted average price (in $ per share)			$ 105.68		$ 104.63
Total cost of shares repurchased			$ 7,501	$ 5,001	$ 30,000	$ 12,501
Shares available for repurchase (in shares)			338,183		338,183
Public offering | Convertible preferred stock
Equity, Class of Treasury Stock [Line Items]
Convertible preferred stock dividend rate		7.25%
Minimum | Forecast | Common stock
Equity, Class of Treasury Stock [Line Items]
Convertible preferred stock converted shares (in shares)	0.7605
Convertible preferred stock (in $ per share)	$ 109.58
Maximum | Forecast | Common stock
Equity, Class of Treasury Stock [Line Items]
Convertible preferred stock converted shares (in shares)	0.9126
Convertible preferred stock (in $ per share)	$ 131.49