Fees and Commissions Revenue Fees and Commissions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020		Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total fees and commissions	$ 192,724		$ 160,552
Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	192,724		160,552
Fees and commission revenue not from contracts with customers	85,010	[1]	53,380	[2]
Fees and commissions revenue from contracts with customers	107,714	[3]	107,172	[4]
Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	50,779		31,617
Fees and commission revenue not from contracts with customers	39,435	[1]	20,826	[2]
Fees and commissions revenue from contracts with customers	11,344	[3]	10,791	[4]
Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	34,384		12,920
Fees and commission revenue not from contracts with customers	34,384	[1]	12,920	[2]
Fees and commissions revenue from contracts with customers	0	[3]	0	[4]
Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	3,223		6,677
Fees and commission revenue not from contracts with customers	3,223	[1]	6,677	[2]
Fees and commissions revenue from contracts with customers	0	[3]	0	[4]
Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	4,343		4,022
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	4,343	[3]	4,022	[4]
Insurance brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	3,789		4,108
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	3,789		4,108
Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	5,040		3,890
Fees and commission revenue not from contracts with customers	1,828	[1]	1,229	[2]
Fees and commissions revenue from contracts with customers	3,212	[3]	2,661	[4]
Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	21,881		20,738
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	21,881	[3]	20,738	[4]
TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	19,026		18,596
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	19,026	[3]	18,596	[4]
Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2,319		2,062
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	2,319	[3]	2,062	[4]
Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	536		80
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	536	[3]	80	[4]
Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	44,458		43,358
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	44,458	[3]	43,358	[4]
Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	20,649		19,574
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	20,649	[3]	19,574	[4]
Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	6,362		6,201
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	6,362	[3]	6,201	[4]
Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	11,757		11,107
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	11,757	[3]	11,107	[4]
Investment management services and other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	5,690		6,476
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	5,690	[3]	6,476	[4]
Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	26,130		28,243
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	26,130	[3]	28,243	[4]
Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	11,993		12,783
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	11,993	[3]	12,783	[4]
Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	7,278		8,260
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	7,278	[3]	8,260	[4]
Check card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	5,229		5,156
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	5,229	[3]	5,156	[4]
Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	1,630		2,044
Fees and commission revenue not from contracts with customers	0	[1]	0	[2]
Fees and commissions revenue from contracts with customers	1,630	[3]	2,044	[4]
Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	37,167		23,834
Fees and commission revenue not from contracts with customers	37,167	[1]	23,834	[2]
Fees and commissions revenue from contracts with customers	0	[3]	0	[4]
Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	21,569		7,868
Fees and commission revenue not from contracts with customers	21,569	[1]	7,868	[2]
Fees and commissions revenue from contracts with customers	0	[3]	0	[4]
Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	15,598		15,966
Fees and commission revenue not from contracts with customers	15,598	[1]	15,966	[2]
Fees and commissions revenue from contracts with customers	0	[3]	0	[4]
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	12,309		12,762
Fees and commission revenue not from contracts with customers	8,408	[1]	8,720	[2]
Fees and commissions revenue from contracts with customers	3,901	[3]	4,042	[4]
Operating Segments [Member] | Commercial [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	41,459		38,046
Operating Segments [Member] | Commercial [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	4,405		2,964
Operating Segments [Member] | Commercial [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2,525		1,575
Operating Segments [Member] | Commercial [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Insurance brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	1,880		1,389
Operating Segments [Member] | Commercial [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	21,037		19,659
Operating Segments [Member] | Commercial [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	18,212		17,654
Operating Segments [Member] | Commercial [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2,305		1,925
Operating Segments [Member] | Commercial [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	520		80
Operating Segments [Member] | Commercial [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Investment management services and other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	11,317		10,294
Operating Segments [Member] | Commercial [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	11,039		10,062
Operating Segments [Member] | Commercial [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	49		74
Operating Segments [Member] | Commercial [Member] | Check card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	229		158
Operating Segments [Member] | Commercial [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Commercial [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	4,700		5,129
Operating Segments [Member] | Consumer [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	55,062		42,821
Operating Segments [Member] | Consumer [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Insurance brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	845		972
Operating Segments [Member] | Consumer [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	831		958
Operating Segments [Member] | Consumer [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	14		14
Operating Segments [Member] | Consumer [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Investment management services and other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Consumer [Member] | Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	14,230		15,439
Operating Segments [Member] | Consumer [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	410		387
Operating Segments [Member] | Consumer [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	7,205		8,395
Operating Segments [Member] | Consumer [Member] | Check card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	5,229		4,992
Operating Segments [Member] | Consumer [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	1,386		1,665
Operating Segments [Member] | Consumer [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	37,611		24,313
Operating Segments [Member] | Consumer [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	21,569		7,868
Operating Segments [Member] | Consumer [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	16,042		16,445
Operating Segments [Member] | Consumer [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2,376		2,097
Operating Segments [Member] | Wealth Management [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	97,881		73,256
Operating Segments [Member] | Wealth Management [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	45,811		25,602
Operating Segments [Member] | Wealth Management [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	34,384		12,920
Operating Segments [Member] | Wealth Management [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	135		5,728
Operating Segments [Member] | Wealth Management [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	4,343		4,074
Operating Segments [Member] | Wealth Management [Member] | Insurance brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	3,789		379
Operating Segments [Member] | Wealth Management [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	3,160		2,501
Operating Segments [Member] | Wealth Management [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(3)		(17)
Operating Segments [Member] | Wealth Management [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(19)		(17)
Operating Segments [Member] | Wealth Management [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Wealth Management [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	16		0
Operating Segments [Member] | Wealth Management [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	44,499		41,683
Operating Segments [Member] | Wealth Management [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	20,649		19,574
Operating Segments [Member] | Wealth Management [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	6,362		6,201
Operating Segments [Member] | Wealth Management [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	11,757		11,107
Operating Segments [Member] | Wealth Management [Member] | Investment management services and other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	5,731		4,801
Operating Segments [Member] | Wealth Management [Member] | Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	580		731
Operating Segments [Member] | Wealth Management [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	545		527
Operating Segments [Member] | Wealth Management [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	22		27
Operating Segments [Member] | Wealth Management [Member] | Check card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Wealth Management [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	13		177
Operating Segments [Member] | Wealth Management [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Wealth Management [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Wealth Management [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0
Operating Segments [Member] | Wealth Management [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	6,994		5,257
Funds Management and Other [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(1,678)		6,429	[5]
Funds Management and Other [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	563		3,051	[5]
Funds Management and Other [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	563		(626)	[5]
Funds Management and Other [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		(52)	[5]
Funds Management and Other [Member] | Insurance brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		3,729	[5]
Funds Management and Other [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2		124	[5]
Funds Management and Other [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2		1	[5]
Funds Management and Other [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		123	[5]
Funds Management and Other [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(41)		1,675	[5]
Funds Management and Other [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Investment management services and other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(41)		1,675	[5]
Funds Management and Other [Member] | Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	3		1,779	[5]
Funds Management and Other [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(1)		1,807	[5]
Funds Management and Other [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2		(236)	[5]
Funds Management and Other [Member] | Check card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		164	[5]
Funds Management and Other [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	2		44	[5]
Funds Management and Other [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(444)		(479)	[5]
Funds Management and Other [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	0		0	[5]
Funds Management and Other [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	(444)		(479)	[5]
Funds Management and Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	$ (1,761)		$ 279	[5]

[1] Out of scope revenue generally relates to financial instruments or contractual rights and obligations within the scope of other applicable accounting guidance.

[2] Out of scope revenue generally relates to financial instruments or contractual rights and obligations within the scope of other applicable accounting guidance.

[3] In scope revenue represents revenue subject to FASB ASC Topic 606, Revenue from Contracts with Customers.

[4] In scope revenue represents revenue subject to FASB ASC Topic 606, Revenue from Contracts with Customers.

[5] CoBiz operations are included in Funds Management and Other for the first quarter of 2019.