Condensed Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share (in dollars per share)	$ 0.15	$ 0.14	$ 0.45	$ 0.42