Allowance for Loan Losses - Summary of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				$ 56,390				$ 52,775	$ 56,390	$ 52,775
Charge-offs									(14,589)	(13,496)
Recoveries									4,200	3,228
Net (Charge-offs) Recoveries									(10,389)	(10,268)
Provision for loan losses	$ 2,716	$ 462	$ 9,345	2,472	$ 982	$ 2,850	$ 4,869	5,183	14,995	13,883	$ 17,965
Balance at End of Year	60,996				56,390				60,996	56,390	52,775
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				27,235				19,976	27,235	19,976
Charge-offs									(372)	(2,304)
Recoveries									309	810
Net (Charge-offs) Recoveries									(63)	(1,494)
Provision for loan losses									6,535	8,753
Balance at End of Year	33,707				27,235				33,707	27,235	19,976
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				8,966				10,810	8,966	10,810
Charge-offs									(8,574)	(4,709)
Recoveries									1,723	654
Net (Charge-offs) Recoveries									(6,851)	(4,055)
Provision for loan losses									9,481	2,211
Balance at End of Year	11,596				8,966				11,596	8,966	10,810
Commercial construction
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				13,167				13,999	13,167	13,999
Charge-offs	(2,400)								(2,630)	(2,571)
Recoveries									1,135	851
Net (Charge-offs) Recoveries									(1,495)	(1,720)
Provision for loan losses									(3,689)	888
Balance at End of Year	7,983				13,167				7,983	13,167	13,999
Consumer real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				5,479				6,095	5,479	6,095
Charge-offs									(1,319)	(2,274)
Recoveries									541	342
Net (Charge-offs) Recoveries									(778)	(1,932)
Provision for loan losses									1,486	1,316
Balance at End of Year	6,187				5,479				6,187	5,479	6,095
Other consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year				$ 1,543				$ 1,895	1,543	1,895
Charge-offs									(1,694)	(1,638)
Recoveries									492	571
Net (Charge-offs) Recoveries									(1,202)	(1,067)
Provision for loan losses									1,182	715
Balance at End of Year	$ 1,523				$ 1,543				$ 1,523	$ 1,543	$ 1,895