Fees and Commissions Revenue Fees and Commissions (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019		Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total fees and commissions		$ 160,552		$ 159,614
Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		160,552		159,614
Fees and commission revenue not from contracts with customers	[1]	53,380		57,371
Fees and commissions revenue from contracts with customers	[2]	107,172		102,243
Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		31,617		30,648
Fees and commission revenue not from contracts with customers	[1]	20,826		22,362
Fees and commissions revenue from contracts with customers	[2]	10,791		8,286
Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		12,920		10,394
Fees and commission revenue not from contracts with customers	[1]	12,920		10,394
Fees and commissions revenue from contracts with customers	[2]	0		0
Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		6,677		10,907
Fees and commission revenue not from contracts with customers	[1]	6,677		10,907
Fees and commissions revenue from contracts with customers	[2]	0		0
Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		4,022		4,599
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	4,022		4,599
Insurance brokerage revenue [Member] [Domain]
Disaggregation of Revenue [Line Items]
Total fees and commissions		4,108		155
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers		4,108		155
Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		3,890		4,593
Fees and commission revenue not from contracts with customers	[1]	1,229		1,061
Fees and commissions revenue from contracts with customers	[2]	2,661		3,532
Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		20,738		20,990
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	20,738		20,990
TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		18,596		19,171
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	18,596		19,171
Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		2,062		1,819
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	2,062		1,819
Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		80		0
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	80		0
Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		43,358		41,832
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	43,358		41,832
Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		19,574		20,100
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	19,574		20,100
Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		6,201		5,641
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	6,201		5,641
Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		11,107		11,450
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	11,107		11,450
Investment management services and other [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		6,476		4,641
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	6,476		4,641
Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		28,243		27,161
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	28,243		27,161
Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		12,783		11,908
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	12,783		11,908
Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		8,260		8,612
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	8,260		8,612
Check card fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		5,156		4,918
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	5,156		4,918
Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		2,044		1,723
Fees and commission revenue not from contracts with customers	[1]	0		0
Fees and commissions revenue from contracts with customers	[2]	2,044		1,723
Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		23,834		26,025
Fees and commission revenue not from contracts with customers	[1]	23,834		26,025
Fees and commissions revenue from contracts with customers	[2]	0		0
Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		7,868		9,452
Fees and commission revenue not from contracts with customers	[1]	7,868		9,452
Fees and commissions revenue from contracts with customers	[2]	0		0
Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		15,966		16,573
Fees and commission revenue not from contracts with customers	[1]	15,966		16,573
Fees and commissions revenue from contracts with customers	[2]	0		0
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		12,762		12,958
Fees and commission revenue not from contracts with customers	[1]	8,720		8,984
Fees and commissions revenue from contracts with customers	[2]	4,042		3,974
Operating Segments [Member] | Commercial [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		38,046		40,017
Operating Segments [Member] | Commercial [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		2,964		3,083
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		1,575		2,022
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] [Domain]
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		1,389		1,061
Operating Segments [Member] | Commercial [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		19,659		20,006
Operating Segments [Member] | Commercial [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		17,654		18,202
Operating Segments [Member] | Commercial [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		1,925		1,804
Operating Segments [Member] | Commercial [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		80		0
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 [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		10,294		11,071
Operating Segments [Member] | Commercial [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		10,062		10,944
Operating Segments [Member] | Commercial [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		74		90
Operating Segments [Member] | Commercial [Member] | Check card fee 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		158		37
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		5,129		5,857
Operating Segments [Member] | Consumer [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		42,821		44,963
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] [Domain]
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		972		1,002
Operating Segments [Member] | Consumer [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		958		987
Operating Segments [Member] | Consumer [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		14		15
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 [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		15,439		15,420
Operating Segments [Member] | Consumer [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		387		359
Operating Segments [Member] | Consumer [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		8,395		8,484
Operating Segments [Member] | Consumer [Member] | Check card fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		4,992		4,918
Operating Segments [Member] | Consumer [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		1,665		1,659
Operating Segments [Member] | Consumer [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		24,313		26,479
Operating Segments [Member] | Consumer [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		7,868		9,452
Operating Segments [Member] | Consumer [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		16,445		17,027
Operating Segments [Member] | Consumer [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		2,097		2,062
Operating Segments [Member] | Wealth Management [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		73,256		74,807
Operating Segments [Member] | Wealth Management [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		25,602		25,743
Operating Segments [Member] | Wealth Management [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		12,920		10,394
Operating Segments [Member] | Wealth Management [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		5,728		6,965
Operating Segments [Member] | Wealth Management [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		4,074		4,697
Operating Segments [Member] | Wealth Management [Member] | Insurance brokerage revenue [Member] [Domain]
Disaggregation of Revenue [Line Items]
Total fees and commissions		379		155
Operating Segments [Member] | Wealth Management [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		2,501		3,532
Operating Segments [Member] | Wealth Management [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		(17)		(19)
Operating Segments [Member] | Wealth Management [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		(17)		(19)
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		0		0
Operating Segments [Member] | Wealth Management [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		41,683		41,880
Operating Segments [Member] | Wealth Management [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		19,574		20,100
Operating Segments [Member] | Wealth Management [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		6,201		5,641
Operating Segments [Member] | Wealth Management [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		11,107		11,450
Operating Segments [Member] | Wealth Management [Member] | Investment management services and other [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		4,801		4,689
Operating Segments [Member] | Wealth Management [Member] | Deposit service charges and fees [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		731		665
Operating Segments [Member] | Wealth Management [Member] | Commercial account service charge revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		527		605
Operating Segments [Member] | Wealth Management [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions		27		34
Operating Segments [Member] | Wealth Management [Member] | Check card fee 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		177		26
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		5,257		6,538
Funds Management and Other [Member] | Fees and commissions revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	6,429		(173)
Funds Management and Other [Member] | Brokerage and trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	3,051		1,822
Funds Management and Other [Member] | Trading revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Customer hedging revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	(626)		1,920
Funds Management and Other [Member] | Retail brokerage revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	(52)		(98)
Funds Management and Other [Member] | Insurance brokerage revenue [Member] [Domain]
Disaggregation of Revenue [Line Items]
Total fees and commissions		3,729	[3]	0
Funds Management and Other [Member] | Investment banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Transaction card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	124		1
Funds Management and Other [Member] | TransFund EFT network revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	1		1
Funds Management and Other [Member] | Merchant services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	123		0
Funds Management and Other [Member] | Corporate card revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Fiduciary and asset management revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	1,675		(48)
Funds Management and Other [Member] | Personal trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Corporate trust revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Institutional trust & retirement plan services revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Investment management services and other [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	1,675		(48)
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	[3]	1,807		0
Funds Management and Other [Member] | Overdraft fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	(236)		4
Funds Management and Other [Member] | Check card fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	164		0
Funds Management and Other [Member] | Automated service charge and other deposit fee revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	44		1
Funds Management and Other [Member] | Mortgage banking revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	(479)		(454)
Funds Management and Other [Member] | Mortgage production revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	0		0
Funds Management and Other [Member] | Mortgage servicing revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	(479)		(454)
Funds Management and Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Total fees and commissions	[3]	$ 279		$ (1,499)

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

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

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