Earnings Per Share - (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reconciliation of number of shares used in calculation of basic and diluted earnings per share
Weighted average number of common shares outstanding	82,872,330	84,941,932	83,625,142	85,443,607
Effect of non-participatory equity compensation (in shares)	40,000	40,000	40,000	40,000
Weighted average number of common shares outstanding, including effect of dilutive securities	82,912,330	84,981,932	83,665,142	85,483,607