Common Shares, Redeemable Common Shares and Preferred Shares (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of stock by class [Table Text Block]

Common and Redeemable Shares Outstanding--The table below reconciles the activity of the common and redeemable shares outstanding:

	Common Shares Net of Treasury Shares		Redeemable Shares		Total
Shares outstanding, December 31, 2016	17,866,236		7,056,904		24,923,140
Shares purchased	(807,718	)	(890,009	)	(1,697,727	)
Shares sold	362,674		300,132		662,806
Stock subscription offering, employee cash purchases	90,645		—		90,645
Options exercised	241,995		—		241,995
Shares outstanding, December 31, 2017	17,753,832		6,467,027		24,220,859
Shares purchased	(1,530,528	)	(1,106,415	)	(2,636,943	)
Shares sold	679,197		281,543		960,740
Stock subscription offering, employee cash purchases	129,245		—		129,245
Options exercised	206,751		—		206,751
Shares outstanding, December 31, 2018	17,238,497		5,642,155		22,880,652