Goodwill and Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of core deposit intangibles and other intangibles
Amortization of other intangible assets	$ 8,159	$ 1,959	$ 2,093
Core Deposit Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount	58,100	4,385	4,385
Accumulated amortization	(5,326)	(4,385)	(4,273)
Net book value	52,774	0	112
Amortization of other intangible assets	5,326	112	281
Adjustments to Core Deposits [Member]
Summary of core deposit intangibles and other intangibles
Additions during the period	58,100	0	0
Other Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount	44,931	34,572	32,410
Reductions due to sale	(43)	0	0
Accumulated amortization	(21,825)	(18,992)	(17,145)
Net book value	23,062	15,580	15,265
Additions during the period	10,359	2,162	1,012
Amortization of other intangible assets	$ 2,833	$ 1,847	$ 1,812