Goodwill and Other Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Summary of core deposit intangibles and other intangibles
Amortization during the year	$ 2,814	$ 2,226
Core Deposit Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount at the beginning of the year	80,730		$ 58,100
Accumulated amortization	(14,597)		(12,456)
Net book value	73,512		68,274
Amortization during the year	2,141		7,130
Adjustments to Core Deposits [Member]
Summary of core deposit intangibles and other intangibles
Additions during the period	7,379		22,630
Adjustments to Other Intangibles [Member]
Summary of core deposit intangibles and other intangibles
Additions during the period	200		0
Other Intangibles
Summary of core deposit intangibles and other intangibles
Gross carrying amount at the beginning of the year	38,970		44,887
Reductions due to sale	(343)		(217)
Accumulated amortization	(19,616)		(24,643)
Net book value	19,211		20,027
Amortization during the year	$ 673		$ 2,818