Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 47,129	$ 18,651
Available for sale securities:
Unrealized gains arising during the period	12,740	7,979
Reclassification adjustment for net gains realized in earnings (net of tax expense of $45 and $0 for the three months ended March 31, 2015 and 2014)	(71)	0
Income tax expense related to unrealized gains	(5,096)	(3,192)
Net change in unrealized gains	7,573	4,787
Held to maturity securities:
Accretion of unrealized losses related to factors other than credit to investment securities held to maturity (net of tax benefit of $0 and $6 for the three months ended March 31, 2015 and 2014)	0	10
Net change in unrealized losses related to factors other than credit	0	10
Other comprehensive income, net of tax	7,573	4,797
Comprehensive income	$ 54,702	$ 23,448