Fair Value Measurement:

6 Months Ended

Jun. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurement [Text Block]

Fair Value Measurement:

Our investment securities consist of certificates of deposit, corporate bonds, sovereign bonds and federal tax-exempt state and municipal government debt. All investment securities are considered available-for-sale and are “investment grade”, carried at fair value, and there have been no gains or losses on their disposal. As of June 30, 2013, we had $5.1 million of our investment securities as Level 1 assets, which are certificates of deposit with quoted prices in active markets, and $68.3 million of our investment securities as Level 2 assets, which are pre-refunded municipal securities, non-pre-refunded municipal securities, corporate bonds and sovereign bonds and have observable market based inputs such as quoted prices, interest rates and yield curves. We had no Level 3 investments for the three and six months endedJune 30, 2013 and June 30, 2012. The following table provides the assets and liabilities carried at fair value measured on a recurring basis.

	Fair value measurements at June 30, 2013 using
	Total carrying value		Quoted prices in active markets for identical assets (level 1)		Significant other observable inputs (level 2)		Significant unobservable inputs (level 3)
Available for sale securities	$	73,395	$	5,060	$	68,335	$	—
	$	73,395	$	5,060	$	68,335	$	—

	Fair value measurements at December 31, 2012 using
	Total carrying value		Quoted prices in active markets for identical assets (level 1)		Significant other observable inputs (level 2)		Significant unobservable inputs (level 3)
Available for sale securities	$	79,259	$	8,490	$	70,769	$	—
	$	79,259	$	8,490	$	70,769	$	—