Shareholders' Equity - Summary of Common Shares Outstanding (Details) - shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Roll forward of common shares outstanding
Balance at the beginning of the year	32,938,466	32,762,494
Restricted share issuances	148,577	170,832
Balance at the end of the period	33,087,043	32,933,326