Equity Transactions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended
	Feb. 01, 2020	May 15, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity, Class of Treasury Stock [Line Items]
Common stock cash dividends declared per share (in $ per share)		$ 0.55	$ 0.55	$ 0.45	$ 1.10	$ 0.90
Preferred stock cash dividends declared per share (in $ per share)		$ 1.8125	$ 1.8125	$ 1.8125	$ 3.625	$ 3.625
Repurchases of common shares (in shares)			67,709		215,671
Weighted average price (in $ per share)			$ 110.74		$ 104.29
Total cost of shares repurchased			$ 7,500	$ 7,500	$ 22,499	$ 7,500
Shares available for repurchase (in shares)			409,132		409,132
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)	0.7598
Convertible Preferred Stock, Shares Issued Upon Conversion, Price Per Share	$ 109.68
Maximum | Forecast | Common Stock
Equity, Class of Treasury Stock [Line Items]
Convertible preferred stock converted shares (in shares)	0.9118
Convertible Preferred Stock, Shares Issued Upon Conversion, Price Per Share	$ 131.62