Earnings Per Share (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average number of common shares outstanding, basic (in shares)	53,762,000	53,620,000	53,732,000	53,585,000
Weighted average number of common shares outstanding, diluted (in shares)	53,856,000	53,773,000	53,831,000	53,735,000
Effect of dilutive shares on earnings per share (in usd per share)	$ 0	$ 0	$ 0	$ 0
Antidilutive shares excluded from computation of earnings per share (in shares)	0	0	0	3,000
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive securities (in shares)	73,000	83,000	69,000	78,000
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive securities (in shares)	0	48,000	13,000	52,000
Purchase Match Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive securities (in shares)	21,000	22,000	17,000	20,000