Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) (Parentheticals) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Stockholders' Equity [Abstract]
Common shares issued from treasury stock for stock-based compensation (in shares)	3,426,757	2,604,284
Common shares repurchased (in shares)	3,147,629	0