Investments Other Comprehensive Income Changes (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Total	[1]	$ 5,054	$ (396)	$ (17,609)	$ (1,664)
Available for Sale Securities, Noncurrent
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales		0	468	0	468
Gross gains from sales		0	31	0	31
Gross losses from sales		0	0	0	0
Net investment gain		0	31	0	31
Unrealized gain on available-for-sale securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized gains		7,185	86	29,663	86
Unrealized losses		0	0	0	0
Total		7,185	86	29,663	86
Unrealized gain on available-for-sale securities | Available for Sale Securities, Noncurrent
Schedule of Available-for-sale Securities [Line Items]
Change in net unrealized holding (losses) gains included in Accumulated other comprehensive (loss) income		$ (10,830)	$ 5,719	$ 9,651	$ 6,240

[1] For the three months ended June 30, 2015 and 2014 unrealized holding losses of $12,239 and gains of $309, respectively, were reclassified to Other income, net and gains of $7,185 and $87, respectively, were reclassified to Net investment gains (losses). For the six months ended June 30, 2015 and 2014 unrealized holding losses of $12,054 and gains of $1,577, respectively, were reclassified to Other income, net and gains of $29,663 and 87, respectively, were reclassified to Net investment gains (losses).