Income Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income per share:
Basic weighted average shares outstanding	31,288	31,253	31,072
Dilutive potential common shares	301	435	385
Diluted weighted average shares outstanding	31,589	31,688	31,457
Stock Options [Member]
Income per share:
Anti-dilutive securities excluded from computation of diluted income per share	12	225	304
Performance Stock Units [Member]
Income per share:
Anti-dilutive securities excluded from computation of diluted income per share	0	0	12