Borrowings (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Fair value of collateral	$ 4,200		$ 4,200		$ 7,000
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Due Date, Earliest	2018		2018
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Due Date, Last	2020		2020
Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available	$ 763,600		$ 763,600
FHLB advances	129,100		129,100		25,000
Interest expense related to FHLB advances	$ 496	$ 166	$ 693	$ 332
Minimum
Assets Sold under Agreements to Repurchase [Line Items]
Interest rate range of FHLB advances	1.31%		1.31%
Maximum
Assets Sold under Agreements to Repurchase [Line Items]
Interest rate range of FHLB advances	2.33%		2.33%
U.S. Treasury Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Fair value of collateral	$ 123,400		$ 123,400		$ 99,100