Fair Value of Financial Instruments Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015
Assets measured on nonrecurring basis
Losses on impaired loans charged through allowance for loan losses	$ 7,238	$ 5,837	$ 672	$ 350	$ 128	$ (380)	$ 583	$ 8
Nonrecurring Basis
Assets measured on nonrecurring basis
Losses on impaired loans charged through allowance for loan losses									$ 1,600
Nonrecurring Basis | Significant Other Observable Inputs (Level 2)
Assets measured on nonrecurring basis
Impaired loans, aggregate outstanding principal balance	51,800								51,800
Impaired loans, fair value	$ 43,700								$ 43,700