Consolidated Statements of Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest expense related to derivatives reclassified from accumulated other comprehensive income	$ 3,673	$ 3,766	$ 7,148	$ 8,568
Net security gains reclassified from accumulated other comprehensive income	4,622	3,110	8,148	7,463
Income tax expense reclassified from accumulated other comprehensive income	10,036	3,989	19,936	11,588
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Derivatives
Interest expense related to derivatives reclassified from accumulated other comprehensive income	465	559	971	1,123
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Unrealized Investment Gain (Loss)
Net security gains reclassified from accumulated other comprehensive income	4,622	3,110	8,378	7,463
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Other Comprehensive Income (Loss)
Income tax expense reclassified from accumulated other comprehensive income	$ 1,551	$ 952	$ 2,763	$ 2,365