Income Taxes - Analysis of the Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal income tax rate	35.00%	35.00%	35.00%
Net tax effects of:
State income taxes, net of federal income tax benefit	5.00%	6.00%	5.00%
Tax-exempt interest income	(2.00%)	(1.00%)	(1.00%)
Amortization of LIHC investments	12.00%	6.00%	9.00%
Tax credits	(27.00%)	(14.00%)	(15.00%)
Other	(1.00%)	(1.00%)	(2.00%)
Effective tax rate	22.00%	31.00%	31.00%