Stock-Based Compensation (Narrative) (Details) - $ / shares	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	6,088	4,594	223,495	4,165	5,099	134,257
2004 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Underlying stock option and restricted stock awards available for grant	0						0
2009 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance	6,250,000						6,250,000
Maximum number of shares may be issued pursuant to stock awards, stock units and other stock-based awards							3,125,000
Maximum number of shares subject to grants to any one individual in any one year							500,000
Underlying stock option and restricted stock awards available for grant	2,427,371						2,427,371
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, in years							3 years
Granted							106,384	0
Weighted average fair value of stock awards granted							$ 55.43	$ 55.43
Amortization period of fair value of shares, in months							36 months
Performance Share Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award amount the grantee may earn							0.00%
Performance Share Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target award amount the grantee may earn							200.00%
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted period							3 years
Granted							61,685
Weighted average fair value of stock awards granted							$ 49.40	$ 36.01
Weighted average fair value of stock awards granted							$ 31.34
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Shares							0
Vesting period, start, in years							1 year
Vesting period, in years							10 years
Stock Options [Member] | Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage							33.00%
Stock Options [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage							33.00%
Stock Options [Member] | Share-based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage							33.00%
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted							13,228	0
Weighted average fair value of stock awards granted							$ 34.02
Weighted average fair value of stock awards granted
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted							12,824
Weighted average fair value of stock awards granted							$ 40.54	$ 40.41
Weighted average fair value of stock awards granted							$ 40.54