Reconciliation of Basic and Diluted Shares (Details 2) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restricted stock units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	0	922	0	770
Stock options
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	55	90	55	90
Stock appreciation rights
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	526	1,567	918	1,432
Performance share units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	0	801	212	649