Operating Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) installment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Future Minimum Lease Payments Under Noncancelable Operating Leases [Line Items]
Description of lease | installment	12
Rent expense	$ 3,900	$ 3,800	$ 3,700
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due	27,544
2017	4,156
2018	4,201
2019	4,045
2020	3,995
2021	3,698
Thereafter	$ 7,449
Office Lease
Future Minimum Lease Payments Under Noncancelable Operating Leases [Line Items]
Lease expiration year	2023
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due	$ 10,525
2017	2,171
2018	2,221
2019	2,062
2020	2,011
2021	1,711
Thereafter	349
Ground Lease
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating Leases, Future Minimum Payments Due	17,019
2017	1,985
2018	1,980
2019	1,983
2020	1,984
2021	1,987
Thereafter	$ 7,100
Minimum | Ground Lease
Future Minimum Lease Payments Under Noncancelable Operating Leases [Line Items]
Lease expiration year	2017
Maximum | Ground Lease
Future Minimum Lease Payments Under Noncancelable Operating Leases [Line Items]
Lease expiration year	2054