Share Information - Earnings Per Share Calculation, Share Information (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Weighted average number of common shares used for basic EPS	36,245,193	37,406,061	36,670,565	37,752,472
Effect of dilutive stock options and restricted and deferred stock unit awards	336,636	0	290,021	360,317
Weighted average number of common shares and dilutive potential common stock used in dilutive EPS	36,581,829	37,406,061	36,960,586	38,112,789