Loans and Allowance - Changes in Allowance for Loan Losses by Loan Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Allowance for loan losses:
Beginning balance	$ 67,870	$ 69,366
Provision for losses		2,102
Recoveries on loans	3,600	3,746
Loans charged off	(1,887)	(6,677)
Ending balance	69,583	68,537
Commercial
Allowance for loan losses:
Beginning balance	27,176	25,913
Provision for losses	2,387	358
Recoveries on loans	2,050	1,873
Loans charged off	(706)	(2,773)
Ending balance	30,907	25,371
Commercial Real Estate
Allowance for loan losses:
Beginning balance	23,102	26,703
Provision for losses	(1,257)	(755)
Recoveries on loans	790	1,376
Loans charged off	(277)	(2,346)
Ending balance	22,358	24,978
Consumer
Allowance for loan losses:
Beginning balance	2,515	2,593
Provision for losses	(12)	73
Recoveries on loans	136	209
Loans charged off	(229)	(186)
Ending balance	2,410	2,689
Residential
Allowance for loan losses:
Beginning balance	15,077	14,157
Provision for losses	(1,098)	2,406
Recoveries on loans	604	288
Loans charged off	(675)	(1,372)
Ending balance	13,908	15,479
Finance Leases
Allowance for loan losses:
Beginning balance
Provision for losses	(20)	20
Recoveries on loans	20
Loans charged off
Ending balance		$ 20