Investments in Qualified Affordable Housing Partnerships, Tax Credit and Other Investments, Net (Investments in Qualified Affordable Housing Partnerships, Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
INVESTMENTS IN QUALIFIED AFFORDABLE HOUSING PARTNERSHIPS, TAX CREDIT AND OTHER INVESTMENTS, NET
Investments in qualified affordable housing partnerships, net	$ 162,824	$ 183,917
Accrued expenses and other liabilities — Unfunded commitments	55,815	57,243
Tax credits and other tax benefits recognized	46,698	37,252	$ 38,271
Amortization expense included in income tax expense	$ 38,464	$ 28,206	$ 26,814