Supplemental Cash Flows Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Cash Flows Information [Abstract]
Cash paid for income taxes	$ 28,300,000	$ 20,400,000	$ 13,500,000
Capital Expenditures Incurred but Not yet Paid	900,000	600,000	800,000
Tax Benefit from Stock Options Exercised	7,100,000	3,300,000	15,800,000
Interest Paid	21,100,000	400,000	100,000
Business Combination, Contingent Consideration, Liability	7,000,000	2,500,000	1,000,000
Loss on extinguishment of debt and related interest expense	$ 14,437,000	$ 0	$ 0