Loans, Impaired Loans Recorded Investment, Unpaid Principal Balance, Related Allowance, Average Recorded Investment, and Interest Income Recognized (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 252,542	$ 316,735
Unpaid Principal Balance	275,458	349,045
Related Allowance	25,671	35,054
Average Recorded Investment	275,589	333,439
Interest Income Recognized	$ 5,190	$ 8,784
Net Recorded Investment of the Impaired Loans	82.00%	81.00%
Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	$ 151,058	$ 182,587
Unpaid Principal Balance	159,695	191,333
Related Allowance	25,671	35,054
Average Recorded Investment	160,317	192,891
Interest Income Recognized	4,158	6,939
Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	101,484	134,148
Unpaid Principal Balance	115,763	157,712
Related Allowance	0	0
Average Recorded Investment	115,272	140,548
Interest Income Recognized	1,032	1,845
Commercial and industrial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	154,028	213,271
Unpaid Principal Balance	171,823	240,038
Related Allowance	11,540	21,047
Average Recorded Investment	176,480	222,788
Interest Income Recognized	1,977	3,864
Commercial and industrial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	67,226	99,786
Unpaid Principal Balance	72,343	105,175
Related Allowance	11,540	21,047
Average Recorded Investment	76,082	104,808
Interest Income Recognized	1,050	2,345
Commercial and industrial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	86,802	113,485
Unpaid Principal Balance	99,480	134,863
Related Allowance	0	0
Average Recorded Investment	100,398	117,980
Interest Income Recognized	927	1,519
Commercial real estate — owner occupied
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	19,126	13,983
Unpaid Principal Balance	20,090	14,834
Related Allowance	1,549	23
Average Recorded Investment	19,048	14,599
Interest Income Recognized	192	401
Commercial real estate — owner occupied | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	12,255	5,544
Unpaid Principal Balance	12,374	5,568
Related Allowance	1,549	23
Average Recorded Investment	12,032	5,840
Interest Income Recognized	192	263
Commercial real estate — owner occupied | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,871	8,439
Unpaid Principal Balance	7,716	9,266
Related Allowance	0	0
Average Recorded Investment	7,016	8,759
Interest Income Recognized	0	138
Commercial and business lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	173,154	227,254
Unpaid Principal Balance	191,913	254,872
Related Allowance	13,089	21,070
Average Recorded Investment	195,528	237,387
Interest Income Recognized	2,169	4,265
Commercial and business lending | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	79,481	105,330
Unpaid Principal Balance	84,717	110,743
Related Allowance	13,089	21,070
Average Recorded Investment	88,114	110,648
Interest Income Recognized	1,242	2,608
Commercial and business lending | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	93,673	121,924
Unpaid Principal Balance	107,196	144,129
Related Allowance	0	0
Average Recorded Investment	107,414	126,739
Interest Income Recognized	927	1,657
Commercial real estate — investor
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	17,563	32,908
Unpaid Principal Balance	17,720	33,509
Related Allowance	1,812	3,410
Average Recorded Investment	17,598	37,757
Interest Income Recognized	1,224	2,120
Commercial real estate — investor | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	16,974	26,764
Unpaid Principal Balance	16,988	27,031
Related Allowance	1,812	3,410
Average Recorded Investment	16,992	30,665
Interest Income Recognized	1,224	2,120
Commercial real estate — investor | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	589	6,144
Unpaid Principal Balance	732	6,478
Related Allowance	0	0
Average Recorded Investment	606	7,092
Interest Income Recognized	0	0
Real estate construction
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	689	509
Unpaid Principal Balance	804	648
Related Allowance	75	84
Average Recorded Investment	709	529
Interest Income Recognized	22	31
Real estate construction | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	476	509
Unpaid Principal Balance	586	648
Related Allowance	75	84
Average Recorded Investment	489	529
Interest Income Recognized	22	31
Real estate construction | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	213	0
Unpaid Principal Balance	218	0
Related Allowance	0	0
Average Recorded Investment	220	0
Interest Income Recognized	0	0
Commercial real estate lending
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	18,252	33,417
Unpaid Principal Balance	18,524	34,157
Related Allowance	1,887	3,494
Average Recorded Investment	18,307	38,286
Interest Income Recognized	1,246	2,151
Commercial real estate lending | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	17,450	27,273
Unpaid Principal Balance	17,574	27,679
Related Allowance	1,887	3,494
Average Recorded Investment	17,481	31,194
Interest Income Recognized	1,246	2,151
Commercial real estate lending | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	802	6,144
Unpaid Principal Balance	950	6,478
Related Allowance	0	0
Average Recorded Investment	826	7,092
Interest Income Recognized	0	0
Total commercial
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	191,406	260,671
Unpaid Principal Balance	210,437	289,029
Related Allowance	14,976	24,564
Average Recorded Investment	213,835	275,673
Interest Income Recognized	3,415	6,416
Total commercial | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	96,931	132,603
Unpaid Principal Balance	102,291	138,422
Related Allowance	14,976	24,564
Average Recorded Investment	105,595	141,842
Interest Income Recognized	2,488	4,759
Total commercial | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	94,475	128,068
Unpaid Principal Balance	108,146	150,607
Related Allowance	0	0
Average Recorded Investment	108,240	133,831
Interest Income Recognized	927	1,657
Residential mortgage
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	49,153	43,876
Unpaid Principal Balance	52,102	46,977
Related Allowance	6,893	6,438
Average Recorded Investment	49,582	45,218
Interest Income Recognized	1,363	1,735
Residential mortgage | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	42,684	37,902
Unpaid Principal Balance	45,028	39,979
Related Allowance	6,893	6,438
Average Recorded Investment	43,090	38,608
Interest Income Recognized	1,258	1,551
Residential mortgage | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	6,469	5,974
Unpaid Principal Balance	7,074	6,998
Related Allowance	0	0
Average Recorded Investment	6,492	6,610
Interest Income Recognized	105	184
Home equity
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	10,891	11,176
Unpaid Principal Balance	11,826	12,016
Related Allowance	3,684	3,943
Average Recorded Investment	11,077	11,527
Interest Income Recognized	411	631
Home equity | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	10,351	11,070
Unpaid Principal Balance	11,283	11,909
Related Allowance	3,684	3,943
Average Recorded Investment	10,537	11,420
Interest Income Recognized	411	627
Home equity | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	540	106
Unpaid Principal Balance	543	107
Related Allowance	0	0
Average Recorded Investment	540	107
Interest Income Recognized	0	4
Other consumer
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,092	1,012
Unpaid Principal Balance	1,093	1,023
Related Allowance	118	109
Average Recorded Investment	1,095	1,021
Interest Income Recognized	1	2
Other consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	1,092	1,012
Unpaid Principal Balance	1,093	1,023
Related Allowance	118	109
Average Recorded Investment	1,095	1,021
Interest Income Recognized	1	2
Other consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Total consumer
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	61,136	56,064
Unpaid Principal Balance	65,021	60,016
Related Allowance	10,695	10,490
Average Recorded Investment	61,754	57,766
Interest Income Recognized	1,775	2,368
Total consumer | Loans with a related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	54,127	49,984
Unpaid Principal Balance	57,404	52,911
Related Allowance	10,695	10,490
Average Recorded Investment	54,722	51,049
Interest Income Recognized	1,670	2,180
Total consumer | Loans with no related allowance
Summarize of nonaccrual loans, accruing loans past due 90 days or more, and restructured loans
Recorded Investment	7,009	6,080
Unpaid Principal Balance	7,617	7,105
Related Allowance	0	0
Average Recorded Investment	7,032	6,717
Interest Income Recognized	$ 105	$ 188