Basis of Presentation (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	$ 740	$ 5,834
Other Tax Expense (Benefit)	259	$ 2,042
Other Assets	301,867		$ 292,139
Assets, Total	10,231,387		10,056,972
Long-term debt	247,022		246,975
Liabilities, Total	8,895,400		8,792,311
Liabilities and Equity, Total	$ 10,231,387		10,056,972
Effect of Change [Member]
Other Assets			(2,371)
Assets, Total			(2,371)
Long-term debt			(2,371)
Liabilities, Total			(2,371)
Liabilities and Equity, Total			$ (2,371)