Acquisitions (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary of merger-related expenses
Salaries and employee benefits	$ 323,686	$ 300,178	$ 669,784	$ 566,268
Equipment and net occupancy	65,376	59,670	130,419	116,333
Printing, postage and supplies	11,368	9,723	23,240	18,925
Other costs of operations	186,093	165,975	357,052	302,183
K Bank and Wilmington Trust Corporation Acquisition [Member]
Summary of merger-related expenses
Salaries and employee benefits	3,024	15,305	4,997	15,312
Equipment and net occupancy		25	15	104
Printing, postage and supplies		318		465
Other costs of operations	4,127	21,348	4,867	25,410
Total merger-related expenses	$ 7,151	$ 36,996	$ 9,879	$ 41,291