Tax Credit Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Affordable housing tax credit investment, net	$ 159,502		$ 159,502		$ 170,401
Other tax credit investments, net	64,922		64,922		72,584
Total TCIs, net	224,424		224,424		242,985
Unfunded affordable housing tax credit commitments	19,727		19,727		23,196
Other tax credit investment liabilities	54,623		54,623		59,823
Total unfunded tax credit investment commitments and liabilities	74,350		74,350		$ 83,019
Affordable housing tax credits and other tax benefits	(7,852)	$ (8,555)	(23,002)	$ (23,642)
Other tax credit investment credits and tax benefits	(1,136)	(1,596)	(3,407)	(4,789)
Amortization of affordable housing investments, net of tax benefit	5,649	5,459	16,638	16,376
Deferred tax expense	238	336	715	1,007
Total reduction in income tax expense	(3,101)	(4,356)	(9,056)	(11,048)
Affordable housing tax credits investment	863	839	2,508	2,517
Other tax credit investment amortization	670	798	2,008	2,394
Total amortization of TCIs	$ 1,533	$ 1,637	$ 4,516	$ 4,911