Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended				12 Months Ended
	Feb. 13, 2018	Aug. 14, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 02, 2017	May 01, 2017
Class of Stock [Line Items]
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01				$ 0.01	$ 0.01
Dividend per share to common stockholders, paid (in dollars per share)				$ 0.3	$ 0.3	$ 0.3	1.20	$ 1.20	$ 1.20
Dividends per share to common stockholders, declared (in dollars per share)			$ 0.30				$ 1.20
Common stock, authorized shares			300,000,000				300,000,000	150,000,000		300,000,000	150,000,000
Number of common shares authorized to be repurchased (shares)			3,000,000				3,000,000
Dividend Declared [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Dividends per share to common stockholders, declared (in dollars per share)	$ 0.30
Common Stock [Member]
Class of Stock [Line Items]
Issuance of common stock (shares)		8,337,500					8,395,607	14,063,100	2,493,171
Price per share (dollars per share)		$ 30.90
Proceeds from Issuance or Sale of Equity		$ 247.1