Income Taxes - Income Tax Expense Components and Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
Federal									$ 95,116	$ (8,471)	$ 9,424
State									16,206	23,154	13,251
Foreign									3,420	5,148	4,435
Total									114,742	19,831	27,110
Deferred
Federal									(70,261)	40,038	54,858
State									(4,579)	(9,564)	3,722
Foreign									(1)	(64)	406
Total									(74,841)	30,410	58,986
Total
Federal									24,855	31,567	64,282
State									11,627	13,590	16,973
Foreign									3,419	5,084	4,841
Income tax expense (benefit)	$ 25,031	$ (4,429)	$ 6,213	$ 13,086	$ 21,375	$ (11,735)	$ 19,314	$ 21,287	$ 39,901	$ 50,241	$ 86,096
Reconciliation of effective income tax rate from the federal income tax rate
Federal income tax rate									21.00%	21.00%	21.00%
Increase (decrease) resulting from:
CARES Act federal NOL carryback									(5.93%)	0.00%	0.00%
Tax credit investments									(4.03%)	(1.94%)	(0.34%)
Executive compensation limitation									3.54%	0.67%	0.36%
State income tax, net of federal tax									3.40%	3.01%	3.34%
Tax-exempt income									(3.04%)	(1.74%)	(1.64%)
FDIC Insurance									1.80%	0.96%	0.25%
Tax basis adjustment									(1.35%)	(3.30%)	0.00%
State tax settlements, net of federal tax									(0.67%)	(1.40%)	0.00%
TCF/Chemical Merger deferred tax reprice									0.00%	(1.59%)	0.00%
Other, net									0.06%	(1.60%)	(1.54%)
Effective income tax rate									14.78%	14.07%	21.43%