Stock-based Compensation (Summary of Restricted Stock Activity) (Details) - $ / shares		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Restricted Stock Units (RSUs) [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, beginning of period, Shares		301,897	384,923
Granted, Shares		143,107	92,409
Vested, Shares		(136,398)	(119,117)
Forfeited, Shares		(27,411)	(31,573)
Outstanding, end of period, Shares		281,195	326,642
Outstanding, beginning of period, Weighted Average Grant Date Fair Value		$ 54.54	$ 45.63
Granted, Weighted Average Grant Date Fair Value		83.43	70.61
Vested, Weighted Average Grant Date Fair Value		42.49	40.94
Forfeited, Weighted Average Grant Date Fair Value		68.07	51.10
Outstanding, end of period, Weighted Average Grant Date Fair Value		$ 73.77	$ 53.88
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, beginning of period, Shares		196,142	218,338
Granted, Shares		118,736	82,025
Vested, Shares		(144,141)	(77,854)
Forfeited, Shares		(63,740)	(14,451)
Outstanding, end of period, Shares	[1]	106,997	208,058
Outstanding, beginning of period, Weighted Average Grant Date Fair Value		$ 47.89	$ 44.24
Granted, Weighted Average Grant Date Fair Value		73.14	48.55
Vested, Weighted Average Grant Date Fair Value		41.11	38.82
Forfeited, Weighted Average Grant Date Fair Value		64.13	44.68
Outstanding, end of period, Weighted Average Grant Date Fair Value	[1]	$ 75.38	$ 47.93

[1] Included in the table above in outstanding shares for the nine months ended September 30, 2015 were 56,500 market-based restricted stock units that were previously granted to the Company's former CEO. These units subsequently forfeited in 2016 and are included above in the amounts forfeited for the nine months ended September 30, 2016.