Income Taxes - Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for credit losses	$ 19,591	$ 20,285
Deferred gain on sale-leaseback transaction	13,752	15,668
Federal net operating loss (NOL) carryforwards	8,871	0
Equity based compensation	3,971	3,605
State NOL carryforwards	3,293	3,384
Non-equity based compensation	2,210	897
OREO	1,460	2,089
Deferred incentives	1,382	29
Property valuation adjustments	1,214	69
AMT and other credit carryforwards	244	667
Other	8,179	12,419
Total deferred tax assets	64,167	59,112
Deferred tax liabilities:
Accrued retirement benefits	(8,502)	(3,517)
Fixed assets	(7,322)	(1,660)
Deferred loan fees and costs	(4,985)	(4,169)
Cancellation of indebtedness income	0	(641)
Acquisition adjustments	(686)	2,489
Other	(2,823)	(2,449)
Total deferred tax liabilities	(24,318)	(9,947)
Deferred tax valuation allowance	0	0
Net deferred tax assets	39,849	49,165
Tax effect of adjustments related to other comprehensive (loss) income	20,280	15,571
Net deferred tax assets including adjustments	60,129	64,736
NOL carryforwards available to offset future taxable income:
AMT credits	0	410
Internal Revenue Service (IRS)
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	42,242	0
Illinois
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	209,802	188,995
Indiana
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	14,260	16,174
Wisconsin
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	$ 1,212	$ 0