Summary of Significant Accounting Policies (Net Income Per Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted Average Number of Shares Outstanding, Basic	72,420	72,000	71,543
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Weighted Average Number of Shares Outstanding, Diluted	73,190	72,854	72,703
Employee Stock Options [Member]
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	148	225	286
Restricted Stock Units (RSUs) [Member]
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	622	629	874