Loans and Leases (Loans and Leases Outstanding) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Acquired	$ 996,280	$ 1,029,426
Originated	12,806,511	12,104,298
Total loans and leases	13,802,791	13,133,724
Commercial
Acquired	702,761	781,307
Originated	9,052,309	8,499,348
Commercial | Construction and land development
Acquired	59,808	78,915
Originated	382,775	319,847
Commercial | Mortgage
Acquired	579,435	642,891
Originated	6,475,366	6,362,490
Commercial | Commercial and industrial
Acquired	25,813	17,254
Originated	1,359,945	1,081,158
Commercial | Lease financing
Originated	443,318	381,763
Commercial | Other commercial real estate
Acquired	36,043	41,381
Originated	177,681	178,754
Commercial | Other
Acquired	1,662	866
Originated	213,224	175,336
Noncommerical
Acquired	293,519	248,119
Originated	3,754,202	3,604,950
Noncommerical | Mortgage
Acquired	240,681	213,851
Originated	1,141,049	982,421
Noncommerical | Construction and land development
Acquired	1,144	2,583
Originated	117,209	122,792
Noncommerical | Revolving mortgage
Acquired	50,048	30,834
Originated	2,120,167	2,113,285
Noncommerical | Consumer
Acquired	1,646	851
Originated	375,777	386,452
Loss Share Agreement [Member]
Acquired	467,900
Temecula Valley Bank [Member] | Loss Share Agreement [Member]
Acquired	191,700
Venture Bank [Member] | Loss Share Agreement [Member]
Acquired	64,400
Sun American Bank [Member] | Loss Share Agreement [Member]
Acquired	50,800
First Regional Bank [Member] | Loss Share Agreement [Member]
Acquired	$ 80,300