Earnings per Common Share Earning per Common Share - Narrative (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted-average number of unvested restricted stock units that participated in the distribution of common dividends (in shares)	2,610,000	0	2,730,000	0
Restricted Stock Units
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted-average number of unvested restricted stock units that participated in the distribution of common dividends (in shares)	1,394,716		1,393,058