Employee Benefits and Share-Based Compensation - Related Stock Activity (Details) - 2009 Plan - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock Units (RSUs)
Number of Shares
Outstanding and unvested December 31	399
Granted (Awarded)	256
Vested (Released)	(196)
Forfeited	(42)
Outstanding and unvested at December 31	417	399
Weighted-Average Grant Date Fair Value
Outstanding and unvested December 31	$ 24.00
Granted (Awarded)	31.44	$ 28.88	$ 19.87
Vested (Released)	23.99
Forfeited	24.65
Outstanding and unvested at December 31	$ 28.49	$ 24.00
Weighted-Average Remaining Years	1 year 7 months	1 year 6 months
Aggregate Intrinsic Value
Non-vested at December 31, 2015	$ 12,948
Fair value of restricted stock units	4,700	$ 3,200	$ 4,400
Unrecognized compensation cost	$ 11,200	$ 8,700
Weighted average period of compensation cost recognized	2 years 10 months 17 days	2 years 7 months 6 days
Restricted Stock
Number of Shares
Outstanding and unvested December 31	36
Granted (Awarded)	36
Vested (Released)	(41)
Forfeited	0
Outstanding and unvested at December 31	31	36
Weighted-Average Grant Date Fair Value
Outstanding and unvested December 31	$ 26.47
Granted (Awarded)	36.05	$ 26.42	$ 18.20
Vested (Released)	26.48
Forfeited	0.00
Outstanding and unvested at December 31	$ 35.97	$ 26.47
Aggregate Intrinsic Value
Fair value of restricted stock units	$ 1,100	$ 1,000	$ 1,100
Unrecognized compensation cost	$ 400	$ 400
Weighted average period of compensation cost recognized	4 months 15 days	6 months