Share Information - Earnings Per Share Calculation (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Weighted average number of common shares used for basic EPS (in shares)	34,462,579	36,245,193	34,977,469	36,670,565
Effect of dilutive stock options and restricted and deferred stock unit awards (in shares)	518,411	336,636	462,562	290,021
Weighted average number of common shares and dilutive potential common stock used in dilutive EPS (in shares)	34,980,990	36,581,829	35,440,031	36,960,586