Significant Accounting Policies (Details 4) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Summary of changes in accumulated other comprehensive income [Roll Forward]
Beginning balance accumulated other comprehensive income	$ 21,080,000		$ 12,480,000
Other comprehensive income before reclassifications, net of tax	8,261,000	[1]	6,467,000	[1]
Amounts reclassified from accumulated other comprehensive income	(341,000)	[2]	(1,163,000)	[2]
Net current period other comprehensive income	7,920,000		5,304,000
Ending balance accumulated other comprehensive income	29,000,000		17,784,000
Income tax expense included in other comprehensive income	$ 5,400,000		$ 3,600,000

[1] Other comprehensive income includes income tax expense of $5.4 million and $3.6 million for the three months ended March 31, 2014 and 2013, respectively.

[2] Included in gain on investments, net on our condensed consolidated statement of operations.