Net Carrying Value of Goodwill (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Gross carrying value of goodwill and the accumulated impairment charge
Gross carrying value		$ 180,797	$ 180,797
Accumulated impairment charge	[1]	(40,159)	(40,159)
Net carrying value		$ 140,638	$ 140,638	$ 130,843	$ 129,706

[1] A goodwill impairment charge was recognized in 2011 and was due to high levels of volatility and dislocation in bank stock prices nationwide.