Other Noninterest Income and Other Noninterest Expense (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	$ 207,842,000	$ 193,014,000	$ 179,315,000
Loans Acquired With Deteriorated Credit Quality [Member]
Other Operating Cost and Expense [Line Items]
Proceeds from Recoveries of Loans Previously Charged off	16,200,000	29,700,000	10,500,000
Telecommunication
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	10,834,000	10,033,000	11,131,000
Cardholder Reward Programs
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	11,435,000	10,154,000	4,325,000
Processing Fees Paid To Third Parties
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	17,089,000	15,095,000	14,454,000
Cardholder Processing
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	11,950,000	9,892,000	11,816,000
Merchant Processing
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	39,874,000	35,279,000	33,313,000
Collection
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	11,595,000	21,209,000	25,591,000
Consultant
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	10,168,000	9,740,000	3,914,000
Advertising
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	11,461,000	8,286,000	3,897,000
Other Expense
Other Operating Cost and Expense [Line Items]
Other Noninterest Expense	$ 83,436,000	$ 73,326,000	$ 70,874,000