Allowance for Loan Losses - Summary of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 61,479	$ 60,517	$ 60,996	$ 56,390
Charge-offs	(4,700)	(1,234)	(13,391)	(11,311)
Recoveries	423	811	1,743	3,198
Net (Charge-offs)/Recoveries	(4,277)	(423)	(11,648)	(8,113)
Provision for loan losses	4,913	462	12,767	12,279
Balance at End of Period	62,115	60,556	62,115	60,556
Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	32,836	31,232	33,707	27,235
Charge-offs	(2,304)	(141)	(2,833)	(373)
Recoveries	6	64	134	293
Net (Charge-offs)/Recoveries	(2,298)	(77)	(2,699)	(80)
Provision for loan losses	1,292	1,735	823	5,735
Balance at End of Period	31,831	32,890	31,831	32,890
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	13,227	10,874	11,596	8,966
Charge-offs	(1,467)	(181)	(8,379)	(8,403)
Recoveries	210	504	718	985
Net (Charge-offs)/Recoveries	(1,257)	323	(7,661)	(7,418)
Provision for loan losses	2,397	(971)	10,431	8,678
Balance at End of Period	14,366	10,226	14,366	10,226
Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	7,254	11,676	7,983	13,167
Charge-offs	0	0	0	(321)
Recoveries	1	4	4	1,134
Net (Charge-offs)/Recoveries	1	4	4	813
Provision for loan losses	620	(765)	(112)	(3,065)
Balance at End of Period	7,875	10,915	7,875	10,915
Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	6,571	5,241	6,187	5,479
Charge-offs	(404)	(487)	(815)	(916)
Recoveries	102	70	595	393
Net (Charge-offs)/Recoveries	(302)	(417)	(220)	(523)
Provision for loan losses	65	214	367	82
Balance at End of Period	6,334	5,038	6,334	5,038
Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	1,591	1,494	1,523	1,543
Charge-offs	(525)	(425)	(1,364)	(1,298)
Recoveries	104	169	292	393
Net (Charge-offs)/Recoveries	(421)	(256)	(1,072)	(905)
Provision for loan losses	539	249	1,258	849
Balance at End of Period	$ 1,709	$ 1,487	$ 1,709	$ 1,487