Stock Based Compensation Fair Value Assumptions for Stock Options (Details) - Five Year Service Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Risk-free interest rate	1.72%	1.75%	0.88%
Expected volatility	56.37%	57.99%	56.70%
Expected term (in years)	5 years 7 months 6 days	5 years 6 months 30 days	5 years 6 months
Weighted average grant date fair value of options granted during the period	$ 11.07	$ 12.64	$ 11.97