Employee Benefit Plans (Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of RSUs (in thousands)
Beginning balance (in shares)	1,212,100	1,499,500	1,592,600
Granted (in shares)	358,000.0	314,900	392,800
Vested and issued (in shares)	(434,500)	(538,200)	(409,800)
Forfeited (in shares)	(44,800)	(64,100)	(76,100)
Beginning balance (in shares)	1,090,800	1,212,100	1,499,500
Number of Restricted Stock Units, Vested and unissued (in shares)	385,100
Weighted-Average Grant Date Fair Value per Share
Unissued, beginning balance (in dollars per share)	$ 69.47	$ 57.63	$ 51.88
Granted (in dollars per share)	91.21	95.75	75.11
Vested and Issued (in dollars per share)	74.69	50.63	50.40
Forfeited (in dollars per share)	87.43	79.77	65.37
Unissued, ending balance (in dollars per share)	77.19	$ 69.47	$ 57.63
Weighted Average Grant Date Fair Value per Share, Vested and unissued (in dollars per share)	$ 55.97
Weighted Average Remaining Contractual Term (years), Unissued	8 months 12 days
Aggregate Intrinsic Value, Unissued	$ 152.1