Operating Leases (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Other information related to leases [Abstract]
Operating lease cost		$ 1,891	$ 1,912
Variable lease cost		466	586
Total Lease costs		2,357	2,498
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash flows from operating leases		1,949
Right-of-use assets obtained in exchange for lease obligations:		$ 53,029	0
Weighted average remaining lease term		9 years 9 months 18 days
Weighted average discount rate		3.30%
Future minimum lease payments under non-cancellable leases [Abstract]
2019	[1]	$ 5,799
2020		7,675
2021		7,613
2022		7,139
2023		6,812
Thereafter		32,254
Total lease payments		67,292
Less: Interest		10,569
Present value of lease liabilities		$ 56,723		$ 0
Minimum annual lease payments under terms of leases [Abstract]
2019			7,799
2020			7,622
2021			7,555
2022			7,048
2023			6,673
2024 and after			32,722
Total lease payments			$ 69,419
Minimum [Member]
Leases, operating [Abstract]
Operating lease expiration term		2 months		5 months
Maximum [Member]
Leases, operating [Abstract]
Operating lease expiration term		25 years 6 months		25 years 9 months 18 days

[1] Excluding three months ended March 31, 2019.