Goodwill and Other Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013
Net goodwill
Goodwill at beginning of period	$ 486,383	$ 642,622
Acquired goodwill	156,239
Goodwill at end of the period	642,622	642,622
Customer-Relationship Intangibles
Gross Carrying Amount	94,330	94,330
Accumulated Amortization	(46,191)	(53,709)
Net Carrying Amount	48,139	40,621
Core deposit intangibles
Customer-Relationship Intangibles
Gross Carrying Amount	27,710	27,710
Accumulated Amortization	(23,234)	(25,967)
Net Carrying Amount	4,476	1,743
Client advisory contract
Customer-Relationship Intangibles
Gross Carrying Amount	64,433	64,433
Accumulated Amortization	(22,540)	(27,117)
Net Carrying Amount	41,893	37,316
Other client service contracts
Customer-Relationship Intangibles
Gross Carrying Amount	2,187	2,187
Accumulated Amortization	(417)	(625)
Net Carrying Amount	$ 1,770	$ 1,562