Stock-Based Compensation, Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares [Roll Forward]
Exercised (in shares)	0	(500,000)	(1,200,000)
Stock Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	3,417,300
Granted (in shares)	496,600
Exercised (in shares)	(116,200)
Forfeited/cancelled/expired (in shares)	(676,800)
Outstanding at end of year (in shares)	3,120,900	3,417,300
Exercisable at end of year (in shares)	1,473,400
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share)	$ 56.81
Granted (in dollars per share)	63.09
Exercised (in dollars per share)	39.67
Forfeited/cancelled/expired (in dollars per share)	71.11
Outstanding at end of year (in dollars per share)	55.38	$ 56.81
Exercisable at end of year (in dollars per share)	$ 44.23
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	3 years 9 months 3 days
Outstanding options, aggregate intrinsic value	$ 8,231
Exercisable options, weighted-average remaining contractual term	3 years 3 months 3 days
Exercisable options, aggregate intrinsic value	$ 6,997
Service-Based Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	1,046,500
Granted (in shares)	0
Exercised (in shares)	(70,200)
Forfeited/cancelled/expired (in shares)	(13,800)
Outstanding at end of year (in shares)	962,500	1,046,500
Exercisable at end of year (in shares)	775,400
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share)	$ 40.53
Granted (in dollars per share)	0
Exercised (in dollars per share)	32.38
Forfeited/cancelled/expired (in dollars per share)	41.49
Outstanding at end of year (in dollars per share)	41.11	$ 40.53
Exercisable at end of year (in dollars per share)	$ 42.59
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	2 years 10 months 13 days
Outstanding options, aggregate intrinsic value	$ 5,234
Exercisable options, weighted-average remaining contractual term	2 years 9 months 7 days
Exercisable options, aggregate intrinsic value	$ 4,000
Performance-Based Options [Member]
Number of Shares [Roll Forward]
Outstanding at beginning of year (in shares)	2,370,800
Granted (in shares)	496,600
Exercised (in shares)	(46,000.0)
Forfeited/cancelled/expired (in shares)	(663,000.0)
Outstanding at end of year (in shares)	2,158,400	2,370,800
Exercisable at end of year (in shares)	698,100
Weighted-Average Exercise Price [Roll Forward]
Outstanding at beginning of year (in dollars per share)	$ 64.00
Granted (in dollars per share)	63.09
Exercised (in dollars per share)	50.79
Forfeited/cancelled/expired (in dollars per share)	71.73
Outstanding at end of year (in dollars per share)	61.75	$ 64.00
Exercisable at end of year (in dollars per share)	$ 46.06
Remaining Contractual Term and Aggregate Intrinsic Value [Abstract]
Outstanding options, weighted-average remaining contractual term	4 years 1 month 28 days
Outstanding options, aggregate intrinsic value	$ 2,997
Exercisable options, weighted-average remaining contractual term	3 years 9 months 25 days
Exercisable options, aggregate intrinsic value	$ 2,997