Consolidated Statements of Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest expense related to derivatives reclassified from Accumulated Other Comprehensive Income	$ 3,549	$ 3,741	$ 12,117	$ 11,084
Net security gains reclassified from Accumulated Other Comprehensive Income	1,767	825	9,230	2,460
Income tax expense reclassified from Accumulated Other Comprehensive Income	4,945	2,916	16,533	8,769
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Derivatives
Interest expense related to derivatives reclassified from Accumulated Other Comprehensive Income	557	577	1,680	1,671
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Unrealized Investment Gain (Loss)
Net security gains reclassified from Accumulated Other Comprehensive Income	1,807	825	9,270	2,460
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Other Comprehensive Income (Loss)
Income tax expense reclassified from Accumulated Other Comprehensive Income	$ 451	$ 93	$ 2,816	$ 296