Investments in Affordable Housing Limited Liability Entities - Investments in Affordable Housing Limited Liability Entities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investments in affordable housing limited liability entities	$ 90,871	$ 82,399
Accrued expenses and other liabilities - unfunded commitments	56,167	48,973
Amortization expense recognized with respect to investments in affordable housing limited liability entities	9,900	9,600	$ 4,800
Tax credits and other benefits	11,600	12,500	$ 7,100
Carrying amount of VIE investments	90,900	81,900
Maximum exposure to loss on the variable interest entity investments	$ 91,100	$ 81,900