Variable Interest Entities Amortization Expense and Tax Credits and Other Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments in Qualified Affordable Housing Projects
Amortization expense	$ 1,079	$ 1,175	$ 1,270
Tax credits and other tax benefits recognized	$ 436	$ 377	$ 419