Stock-based Compensation - Summary of Restricted Stock Option (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in shares)	855	27	855	27
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted during the period (in shares)	85	569	85	584
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted during the period (in shares)	0	0	0	0