Loans, Allowance for Loan Losses, and Credit Quality Changes in the Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Changes in the allowance for loan losses
Loans and Leases Receivable, Allowance, Beginning Balance	$ 268,315	$ 297,409
Provision for loan losses	5,000	10,000
Charge offs	(11,361)	(88,061)
Recoveries	5,962	48,967
Net charge offs	(5,399)	(39,094)
Loans and Leases Receivable, Allowance, Ending Balance	267,916	268,315
Changes in the allowance for unfunded commitments
Allowance for Credit Losses	289,816	290,215
Reserve for Off-balance Sheet Activities [Member]
Changes in the allowance for unfunded commitments
Balance at beginning of period	21,900	21,800
Provision for unfunded commitments	0	100
Balance at end of period	$ 21,900	$ 21,900