Reconciliation of Basic and Diluted Shares (Details 2) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restricted stock units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	0	957	0	694
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)	972	1,641	1,117	1,364
Performance share units
Antidilutive securities
Number of securities not included in computation of diluted earnings per share (in shares)	176	835	320	572