Investment Securities OTTI Credit Losses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Credit loss portion of other than temporary impairment
Credit-related other-than-temporary impairment	$ (5,514)	$ (6,279)	$ (6,868)
Reduction due to credit impaired securities sold	765	589
Collateralized Mortgage Backed Securities [Member]
Credit loss portion of other than temporary impairment
Credit-related other-than-temporary impairment	0	0	(532)
Reduction due to credit impaired securities sold	0	532
Trust Preferred Debt Securities [Member]
Credit loss portion of other than temporary impairment
Credit-related other-than-temporary impairment	(5,514)	(6,279)	(6,336)
Reduction due to credit impaired securities sold	$ 765	$ 57