Fair Value Measurements (Details 5) (USD $)	6 Months Ended	0 Months Ended
	Jun. 30, 2014	Apr. 30, 2014 ARS	Mar. 31, 2014 ARS	Dec. 31, 2013 ARS
Fair value inputs, Quantitative information
Investment in auction rate securities			$ 46,300,000	$ 46,300,000
Proceeds from sale of securities	44,497,000	44,500,000
Loss on sale of investments	$ 1,786,000	$ 1,800,000