Goodwill and Intangible Assets, Summary of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Summary of core deposit intangibles and other intangibles
Additions during the period	$ 1,000		$ 12,000
Amortization of other intangible assets	504	$ 801
Core Deposit Intangibles [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount	4,385		19,545
Accumulated amortization	(4,062)		(19,152)
Total Estimated Amortization Expense	323		393
Amortization of other intangible assets	70		1,404
Other Intangible Assets [Member]
Summary of core deposit intangibles and other intangibles
Gross carrying amount	32,410		31,398
Accumulated amortization	(15,767)		(15,333)
Total Estimated Amortization Expense	16,643		16,065
Additions during the period	1,012		12,115
Amortization of other intangible assets	$ 434		$ 1,690