Goodwill and Other Intangible Assets (Other Intangibles) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Intangible Assets
Gross intangibles	$ 21,523	$ 21,009
Acquired intangibles	1,593	514
Accumulated amortization	(13,956)	(10,441)
Total acquired intangibles	9,160	11,082
Other intangible assets	11,465	13,387
Core Deposits
Other Intangible Assets
Gross intangibles	16,150	16,150
Acquired intangibles	0	0
Accumulated amortization	(10,281)	(7,594)
Total acquired intangibles	5,869	8,556
Customer Relationships
Other Intangible Assets
Gross intangibles	5,373	4,859
Acquired intangibles	1,593	514
Accumulated amortization	(3,675)	(2,847)
Total acquired intangibles	3,291	2,526
Servicing rights
Other Intangible Assets
Total acquired intangibles	2,305	2,305	$ 2,387	$ 2,238
Other intangible assets	$ 2,305	$ 2,305