Loan Servicing Rights (Activity for Capitalized LSRs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity for Capitalized LSRs
Balance at beginning of period	$ 40,211
Amortization	(6,090)	$ (10,046)	$ (8,444)
Balance at end of period	34,271	40,211
Loan Servicing Rights
Activity for Capitalized LSRs
Balance at beginning of period	$ 10,230	11,122	12,217
Acquired through acquisitions		0	1,284
Additions		3,303	1,476
Amortization		(4,187)	(4,055)
Change in valuation allowance		(8)	200
Balance at end of period		$ 10,230	$ 11,122