Comprehensive Income (AOCI Rollforward) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ 21,975,363
Comprehensive Income	66,074,507	50,805,478
Balance at end of period	19,483,799	22,945,622
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	2,507,922	2,458,933
Other Comprehensive income before reclassifications	(91,250)	(601,749)
Amounts reclassified from accumulated other comprehensive income	0	0
Comprehensive Income	(91,250)	(601,749)
Balance at end of period	2,416,672	1,857,184
Unrealized gains(losses) on available-for-sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	19,467,441	15,111,778
Other Comprehensive income before reclassifications	864,910	7,811,095
Amounts reclassified from accumulated other comprehensive income	(3,265,224)	(1,834,435)
Comprehensive Income	(2,400,314)	5,976,660
Balance at end of period	$ 17,067,127	$ 21,088,438