Dividends - Cash Dividends per Common Share (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Dividends declared (in dollars per share)	$ 0.18875	$ 0.18375	$ 0.37625	$ 0.36625