Comprehensive Income (AOCI Rollforward) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			$ 21,975,363	[1]
Comprehensive Income	74,760,681	49,938,191	140,835,188		100,743,669
Balance at end of period	17,517,734	20,786,416	17,517,734		20,786,416
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	2,416,672	1,857,184	2,507,922		2,458,933
Other Comprehensive income before reclassifications	(241,489)	229,115	(332,739)		(372,634)
Amounts reclassified from accumulated other comprehensive income	0	0	0		0
Comprehensive Income	(241,489)	229,115	(332,739)		(372,634)
Balance at end of period	2,175,183	2,086,299	2,175,183		2,086,299
Unrealized gains(losses) on available-for-sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	17,067,127	21,088,438	19,467,441		15,111,778
Other Comprehensive income before reclassifications	2,527,930	881,260	3,392,840		8,692,354
Amounts reclassified from accumulated other comprehensive income	(4,252,506)	(3,269,581)	(7,517,730)		(5,104,015)
Comprehensive Income	(1,724,576)	(2,388,321)	(4,124,890)		3,588,339
Balance at end of period	$ 15,342,551	$ 18,700,117	$ 15,342,551		$ 18,700,117

[1] Note: The condensed consolidated balance sheet at December 31, 2013 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.