Preferred Stock (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 15, 2019 shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares	Jul. 26, 2016
Class of Stock [Line Items]
Preferred stock dividends | $		$ 0	$ 18,437	$ 34,931
Depository Shares
Class of Stock [Line Items]
Depository shares issued					5,200,000
Preferred stock ownership interest						0.010
6.75% Series B Mandatory Convertible Preferred Stock
Class of Stock [Line Items]
Percentage of issued shares					6.75%
Offering price (in usd per share) | $ / shares					$ 100
Proceeds from offering, net | $					$ 501,000
Preferred stock converted in to common stock (in shares)	132.50
Number of common stock issued upon conversion (in shares)	6,900,000