Consolidated Statements of Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Statement of Stockholders' Equity [Abstract]
Special cash dividends paid to certain common stockholders (in usd per share)		$ 2.26
Common dividends (in usd per share)	$ 0.25	0.34375
Dividends to holders of Series A Preferred Stock (in usd per share)	$ 0.6875	$ 0.6875