Loans (Details 6) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Changes in allowance for loan losses
Beginning balance			$ 47,453
Provision for loan loss			600	$ 2,000
Ending Balance	$ 47,212		47,212
Amount allocated to:
Ending Balance	47,212		47,453		$ 47,212	$ 47,453
Loans:
Ending Balance					2,565,320	2,405,290
Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	40,259	$ 36,937	38,942	34,449
Provision for loan loss	646	760	2,624	6,808
Charged-off	(845)	(623)	(2,306)	(5,040)
Recoveries	431	232	1,231	1,089
Ending Balance	40,491	37,306	40,491	37,306
Amount allocated to:
Loans individually evaluated for impairment					1,332	2,641
Loans collectively evaluated for impairment					39,159	36,301
Ending Balance	40,259	36,937	38,942	34,449	40,491	38,942
Loans:
Loans individually evaluated for impairment					8,039	8,593
Loans collectively evaluated for impairment					2,247,124	2,084,169
Ending Balance					2,255,879	2,092,762
Florida
Changes in allowance for loan losses
Beginning balance	7,461	10,491	8,511	13,118
Provision for loan loss	(546)	(760)	(2,024)	(4,808)
Charged-off	(230)	(62)	(337)	(219)
Recoveries	36	39	571	1,617
Ending Balance	6,721	9,708	6,721	9,708
Amount allocated to:
Loans individually evaluated for impairment					55	527
Loans collectively evaluated for impairment					6,666	7,984
Ending Balance	7,461	10,491	8,511	13,118	6,721	8,511
Loans:
Loans individually evaluated for impairment					14,528	17,993
Loans collectively evaluated for impairment					294,913	294,535
Ending Balance					309,441	312,528
Purchased Credit Impaired Loan [Member] | Illinois/Indiana
Loans:
Loans collectively evaluated for impairment					716
Commercial | Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	9,231	7,695	8,869	8,452
Provision for loan loss	(335)	1,031	(54)	879
Charged-off		(121)	(77)	(825)
Recoveries	55	29	213	128
Ending Balance	8,951	8,634	8,951	8,634
Amount allocated to:
Loans individually evaluated for impairment					220	595
Loans collectively evaluated for impairment					8,731	8,274
Ending Balance	9,231	7,695	8,869	8,452	8,951	8,869
Loans:
Loans individually evaluated for impairment					1,658	2,117
Loans collectively evaluated for impairment					602,636	582,904
Ending Balance					604,294	585,021
Commercial | Florida
Changes in allowance for loan losses
Beginning balance	724	1,782	1,172	1,926
Provision for loan loss	24	(539)	(507)	(807)
Charged-off		(6)		(26)
Recoveries	13	18	96	162
Ending Balance	761	1,255	761	1,255
Amount allocated to:
Loans collectively evaluated for impairment					761	1,172
Ending Balance	724	1,782	1,172	1,926	761	1,172
Loans:
Loans individually evaluated for impairment					553	1,642
Loans collectively evaluated for impairment					16,448	15,097
Ending Balance					17,001	16,739
Commercial real estate | Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	16,938	15,426	16,434	16,379
Provision for loan loss	383	2,208	1,424	2,388
Charged-off	(589)		(1,297)	(1,173)
Recoveries	50	39	221	79
Ending Balance	16,782	17,673	16,782	17,673
Amount allocated to:
Loans individually evaluated for impairment					1,054	1,975
Loans collectively evaluated for impairment					15,728	14,459
Ending Balance	16,938	15,426	16,434	16,379	16,782	16,434
Loans:
Loans individually evaluated for impairment					3,150	3,994
Loans collectively evaluated for impairment					1,009,478	928,914
Ending Balance					1,013,004	932,908
Commercial real estate | Florida
Changes in allowance for loan losses
Beginning balance	4,007	4,976	4,205	5,733
Provision for loan loss	(614)	116	(1,030)	(912)
Recoveries			218	271
Ending Balance	3,393	5,092	3,393	5,092
Amount allocated to:
Loans individually evaluated for impairment					49	370
Loans collectively evaluated for impairment					3,344	3,835
Ending Balance	4,007	4,976	4,205	5,733	3,393	4,205
Loans:
Loans individually evaluated for impairment					5,185	5,688
Loans collectively evaluated for impairment					166,501	165,555
Ending Balance					171,686	171,243
Commercial real estate | Purchased Credit Impaired Loan [Member] | Illinois/Indiana
Loans:
Loans collectively evaluated for impairment					376
Real estate construction | Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	2,054	2,776	2,590	2,540
Provision for loan loss	(66)	(623)	(774)	(241)
Charged-off				(657)
Recoveries	53		225	511
Ending Balance	2,041	2,153	2,041	2,153
Amount allocated to:
Loans individually evaluated for impairment					33	46
Loans collectively evaluated for impairment					2,008	2,544
Ending Balance	2,054	2,776	2,590	2,540	2,041	2,590
Loans:
Loans individually evaluated for impairment					33	46
Loans collectively evaluated for impairment					89,023	89,058
Ending Balance					89,396	89,104
Real estate construction | Florida
Changes in allowance for loan losses
Beginning balance	167	175	205	1,168
Provision for loan loss	2	5	(36)	(1,983)
Recoveries	5		5	995
Ending Balance	174	180	174	180
Amount allocated to:
Loans collectively evaluated for impairment					174	205
Ending Balance	167	175	205	1,168	174	205
Loans:
Loans individually evaluated for impairment					510	551
Loans collectively evaluated for impairment					13,962	17,399
Ending Balance					14,472	17,950
Real estate construction | Purchased Credit Impaired Loan [Member] | Illinois/Indiana
Loans:
Loans collectively evaluated for impairment					340
Retail real estate | Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	11,728	10,802	10,745	6,862
Provision for loan loss	666	(1,986)	1,942	3,540
Charged-off	(200)	(388)	(692)	(2,079)
Recoveries	226	120	425	225
Ending Balance	12,420	8,548	12,420	8,548
Amount allocated to:
Loans individually evaluated for impairment					25	25
Loans collectively evaluated for impairment					12,395	10,720
Ending Balance	11,728	10,802	10,745	6,862	12,420	10,745
Loans:
Loans individually evaluated for impairment					3,062	2,428
Loans collectively evaluated for impairment					530,689	473,611
Ending Balance					533,751	476,039
Retail real estate | Florida
Changes in allowance for loan losses
Beginning balance	2,550	3,554	2,917	4,287
Provision for loan loss	43	(345)	(417)	(1,096)
Charged-off	(230)	(55)	(336)	(192)
Recoveries	13	15	212	170
Ending Balance	2,376	3,169	2,376	3,169
Amount allocated to:
Loans individually evaluated for impairment						150
Loans collectively evaluated for impairment					2,376	2,767
Ending Balance	2,550	3,554	2,917	4,287	2,376	2,917
Loans:
Loans individually evaluated for impairment					8,274	10,105
Loans collectively evaluated for impairment					97,055	95,929
Ending Balance					105,329	106,034
Retail other | Illinois/Indiana
Changes in allowance for loan losses
Beginning balance	308	238	304	216
Provision for loan loss	(2)	130	86	242
Charged-off	(56)	(114)	(240)	(306)
Recoveries	47	44	147	146
Ending Balance	297	298	297	298
Amount allocated to:
Loans collectively evaluated for impairment					297	304
Ending Balance	308	238	304	216	297	304
Loans:
Loans individually evaluated for impairment					136	8
Loans collectively evaluated for impairment					15,298	9,682
Ending Balance					15,434	9,690
Retail other | Florida
Changes in allowance for loan losses
Beginning balance	13	4	12	4
Provision for loan loss	(1)	3	(34)	(10)
Charged-off		(1)	(1)	(1)
Recoveries	5	6	40	19
Ending Balance	17	12	17	12
Amount allocated to:
Loans individually evaluated for impairment					6	7
Loans collectively evaluated for impairment					11	5
Ending Balance	$ 13	$ 4	$ 12	$ 4	17	12
Loans:
Loans individually evaluated for impairment					6	7
Loans collectively evaluated for impairment					947	555
Ending Balance					$ 953	$ 562