Employee Benefit Plans - 401(K) Saving And Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Benefit Plan Compensation
Compensation cost	$ 9,000	$ 7,500	$ 3,600
Non Employee Director Member
Employee Benefit Plan Compensation
Granted (in shares)	105,479	89,490	71,311
Compensation cost	$ 267	$ 267	$ 331
401(k) Savings & Retirement Plan
401(K) Savings & Retirement Plan
Percent of salary employee is permitted to contribute	100.00%
Vesting period	3 years
Common stock, shares issued			74,863
Total expense (including issuance of shares)	$ 1,400	$ 800	$ 400