Capital Stock - Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Oct. 31, 2016
Class of Stock [Line Items]
Dividends on preferred stock		$ 5,283	$ 0
Preferred Class B
Class of Stock [Line Items]
Preferred Stock, shares authorized (shares)	13,000,000	100,000,000
Preferred Stock, dividend rate (percent)		8.00%
Preferred Stock, par value (usd per share)		$ 0.01
Sale of stock price (in USD per share)	$ 25.00
Preferred stock, redemption price per share (in USD per share)	$ 25.00
Preferred Class A
Class of Stock [Line Items]
Preferred Stock, shares authorized (shares)		100,000,000		100,000,000	5,800,000
Preferred Stock, dividend rate (percent)	8.00%	8.00%		8.00%
Preferred Stock, par value (usd per share)	$ 0.01	$ 0.01		$ 0.01
Sale of stock price (in USD per share)	25.00
Issuance of preferred stock (in shares)		$ 314,429
Preferred stock, redemption price per share (in USD per share)	25.00
Fixed dividend amount (in dollars per share)	$ 2.00
Preferred stock, issuance cost and discount on shares					$ 140,000
Dividends on preferred stock		$ 3,000
Preferred stock dividends declared (in USD per share)		$ 0.50
Additional Paid-in Capital | Preferred Class B
Class of Stock [Line Items]
Issuance of preferred stock (in shares)	$ 314,299
London Interbank Offered Rate (LIBOR) | Preferred Class A
Class of Stock [Line Items]
Preferred stock, basis spread on variable rate	5.791%