Lease Obligations - Schedule of Net Operating Lease Expense (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Leases [Abstract]
Lease expense charged to operations		$ 4,426	$ 4,946	$ 8,486	$ 9,943
Accretion of operating lease intangible	[1]		(210)		(505)
Accretion of deferred gain on sale-leaseback transaction	[1]		(1,463)		(2,926)
Rental income from premises leased to others	[1]	(165)	(108)	(322)	(262)
Net operating lease expense		$ 4,261	$ 3,165	$ 8,164	$ 6,250

[1] Included as reductions to net occupancy and equipment expense in the Condensed Consolidated Statements of Income.