Share Information - Earnings Per Share Calculation (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Weighted average number of common shares used for basic EPS (in shares)	32,905,142	34,462,579	33,363,472	34,977,469
Effect of dilutive stock options and restricted and deferred stock unit awards (in shares)	0	518,411	0	462,562
Weighted average number of common shares and dilutive potential common stock used in dilutive EPS (in shares)	32,905,142	34,980,990	33,363,472	35,440,031