Shareholders' Equity - Schedule of Shares Granted and Vested (Details) - Share Award Plans - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Unvested shares at the beginning of the year (in shares)	161,990	148,010	153,410
Shares granted (in shares)	202,500	123,800	103,100
Shares vested/forfeited (in shares)	(137,150)	(109,820)	(108,500)
Unvested shares at the end of the year (in shares)	227,340	161,990	148,010
Weighted Average Grant Date Fair Value
Unvested shares at the beginning of the year (in dollars per share)	$ 19.41	$ 19.71	$ 19.92
Shares granted (in dollars per share)	8.65	18.72	19.99
Shares vested/forfeited (in dollars per share)	8.94	18.31	20.05
Unvested shares at the end of the year (in dollars per share)	$ 12.52	$ 19.41	$ 19.71