Common Stock (Details Textual) - USD ($)		3 Months Ended		12 Months Ended
	May. 06, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Mar. 27, 2015
Class of Stock [Line Items]
Proceeds From Issuance Of Common Stock		$ 1,991,840	$ (94,633)
ATM Program [Member]
Class of Stock [Line Items]
Gross Amount Remaining To Be Issued		$ 57,900,000
Common Stock Average Price		$ 38.38		$ 30.31
Common Stock [Member]
Class of Stock [Line Items]
Registration Payment Arrangement, Maximum Potential Consideration					$ 500,000,000
Shares, Issued				1,725,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)				$ 53,000,000
Common Stock [Member] | ATM Program [Member]
Class of Stock [Line Items]
Proceeds From Issuance Of Common Stock		$ 2,100,000		$ 40,000,000
Value Of Equity Instruments To Be Issued	$ 100,000,000
Stock Issued During Period, Shares, New Issues		53,886		1,318,812