Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Significant Accounting Policies details [Line Items]
Charge off threshold for unsecured commercial loans considered uncollectible			90 days
Charge off threshold for closed-end consumer loans and uncollectible loans			120 days
Number of monthly payments before loan charge off			5
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)	$ (8)	$ 819	$ (8)	$ 819
Tax (benefit) expense	5,026	5,503	10,465	10,917
Net income	11,942	12,232	23,762	24,101
Unrealized Gain (Losses ) on AFS Securities [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses)	(8)	819	(8)	819
Tax (benefit) expense	(3)	315	(3)	315
Net income	$ (5)	$ 504	$ (5)	$ 504
Minimum [Member]
Significant Accounting Policies details [Line Items]
Historical loan loss review period (in quarters)			4
Other real estate owned frequency of period reviews			24 months
Maximum [Member]
Significant Accounting Policies details [Line Items]
Historical loan loss review period (in quarters)			8
Other real estate owned frequency of period reviews			12 months