Loan Servicing Rights - LSRs Activity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Dec. 31, 2016
Loan Servicing Rights
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]		$ 3,659
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		$ 48,085
Transfers based on new accounting policy election		15,891
Additions from loans sold with servicing retained		1,753
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(606)
Changes in estimates of fair value		(519)
Fair value, end of period		64,604
Principal balance of loans serviced for others that have servicing capitalized		7,304,338
Commercial real estate
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		344
Transfers based on new accounting policy election		0
Additions from loans sold with servicing retained		0
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(24)
Changes in estimates of fair value		0
Fair value, end of period		320
Principal balance of loans serviced for others that have servicing capitalized		50,942
Residential mortgage
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		47,741
Transfers based on new accounting policy election		15,891
Additions from loans sold with servicing retained		1,753
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(582)
Changes in estimates of fair value		(519)
Fair value, end of period		64,284
Principal balance of loans serviced for others that have servicing capitalized		$ 7,253,396
Retained earnings
Loan Servicing Rights
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]		$ 3,659

[1] Refer to Footnote 1, Basis of Presentation and Accounting Policies and Footnote 8, Loan Servicing Rights, for further details on this change in accounting policy election.