Loans and Leases (Accretable Yield Movement Schedule) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	$ 165,362	$ 200,527	$ 201,699	$ 127,624
Additions		0		110,757
Accretion to interest income	(14,432)	(18,257)	(42,864)	(52,317)
Disposals	(6,569)	(6,834)	(21,825)	(24,403)
Reclassifications from (to) nonaccretable difference	5,285	8,995	12,636	22,770
Balance, end of period	149,646	184,431	149,646	184,431
Evergreen Bank [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	7,057	10,576	9,466	20,063
Additions		0		0
Accretion to interest income	(1,228)	(1,546)	(3,748)	(9,998)
Disposals	(844)	(320)	(3,227)	(5,061)
Reclassifications from (to) nonaccretable difference	745	2,213	3,239	5,919
Balance, end of period	5,730	10,923	5,730	10,923
Rainier [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	43,242	56,609	49,989	71,789
Additions		0		0
Accretion to interest income	(3,585)	(4,134)	(10,522)	(14,671)
Disposals	(1,468)	(1,051)	(4,081)	(9,658)
Reclassifications from (to) nonaccretable difference	872	3,260	3,675	7,224
Balance, end of period	39,061	54,684	39,061	54,684
Nevada Security Bank [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	17,453	27,837	23,666	34,632
Additions		0		0
Accretion to interest income	(2,107)	(2,798)	(6,822)	(11,792)
Disposals	(1,230)	(1,352)	(3,295)	(5,258)
Reclassifications from (to) nonaccretable difference	1,992	728	2,559	6,833
Balance, end of period	16,108	24,415	16,108	24,415
Circle Bancorp [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	422	965	796	1,140
Additions		0		0
Accretion to interest income	(56)	(36)	(205)	(211)
Disposals	(69)	0	(331)	0
Reclassifications from (to) nonaccretable difference	0	(49)	37	(49)
Balance, end of period	297	880	297	880
Sterling Financial Corporation [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	97,188	104,540	117,782	0
Additions		0		110,757
Accretion to interest income	(7,456)	(9,743)	(21,567)	(15,645)
Disposals	(2,958)	(4,111)	(10,891)	(4,426)
Reclassifications from (to) nonaccretable difference	1,676	2,843	3,126	2,843
Balance, end of period	$ 88,450	$ 93,529	$ 88,450	$ 93,529