Share-Based Compensation (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grant (in shares)	1,185,089		1,185,089
Weighted average period over which unrecognized compensation cost is expected to be recognized			1 year 8 months 12 days
Unamortized share-based compensation expense	$ 14,800,000		$ 14,800,000
Costs for share-based payment arrangements	$ 3,800,000	$ 4,600,000	$ 8,300,000	$ 10,100,000
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted			75,000	175,000
Weighted-Average Grant Date Fair Value, Issued			$ 13.93	$ 20.41
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock options granted			75,000	85,000
Weighted-average exercise prices			$ 25.70	$ 25.62
Stock options expired				750,000
Weighted-average exercise prices, expired				$ 20.33
Weighted average grant date fair value			$ 3.94	$ 7.57
Expected life			6 years
Expected quarterly dividends			$ 0
Expected volatility			44.91%
Risk-free rate			1.56%
Unrestricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units granted			194,177	98,591
Weighted-Average Grant Date Fair Value, Issued			$ 8.60	$ 15.72