Shareholders' Equity - Schedule of Stock Options Outstanding Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Options outstanding, beginning balance (in shares)	667	667
Granted (in shares)	0	0
Exercised (in shares)	0	0
Canceled / forfeited / expired (in shares)	0	0
Options outstanding, ending balance (in shares)	667	667	667
Vested and exercisable (in shares)	0
Weighted-Average Exercise Price
Options outstanding, beginning balance (in dollars per share)	$ 33.75	$ 33.75
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	0	0
Canceled / forfeited / expired (in dollars per share)	0	0
Options outstanding, ending balance (in dollars per share)	33.75	$ 33.75	$ 33.75
Vested and exercisable (in dollars per share)	$ 0
Weighted-Average Remaining Contractual Term, Outstanding (in years)	1 year 3 months	1 year 3 months	1 year 3 months
Weighted-Average Remaining Contractual Term, Vested and exercisable (in years)	0 years
Aggregate Intrinsic Value, Outstanding	$ 0	$ 0	$ 0
Aggregate Intrinsic Value, Vested and exercisable	$ 0