Investment Securities - Amortized cost and fair value of investment securities portfolio excluding equity securities (Details 2) $ in Thousands	Jun. 30, 2016 USD ($)
Amortized cost available-for-sale:
One year or less	$ 8,336
After one year through five years	107,874
After five years through ten years	167,396
After ten years	399,031
Amortized cost	682,637
Estimated fair value available-for-sale:
One year or less	8,354
After one year through five years	110,292
After five years through ten years	169,475
After ten years	408,136
Estimated fair value	$ 696,257