Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Real property leases not yet commenced	$ 247,400	$ 247,400
Operating lease liability incurred for right of use asset	877	6,700
Operating lease payments	2,000	4,000
Right of use assets	40,500	40,500
Operating lease liability	41,403	41,403
2019			$ 7,300
2020			6,200
2021			5,100
2022			4,800
2023			4,400
2024			12,100
Premises and equipment	123,708	123,708	$ 123,442
Underlying assets under operating leases	$ 15,100	$ 15,100
Minimum
Lessee, Lease, Description [Line Items]
Lease term	1 year	1 year
Renewal term	3 years	3 years
Maximum
Lessee, Lease, Description [Line Items]
Lease term	15 years	15 years
Renewal term	5 years	5 years
Affiliated Entity
Lessee, Lease, Description [Line Items]
Lease term	22 years 6 months	22 years 6 months
Real property leases not yet commenced	$ 231,600	$ 231,600
Ownership interest	50.00%	50.00%