|
Fair Value of Available for Sale Securities and Related Gains and Losses Recognized in Accumulated Other Comprehensive Income or Loss (Detail) (USD $)
In Thousands, unless otherwise specified |
Sep. 30, 2012
|
Dec. 31, 2011
|
|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| Amortized Cost | $ 294,962 | $ 317,493 |
| Gross Unrealized Gains | 7,605 | 5,095 |
| Gross Unrealized Losses | (23) | (76) |
| Fair Value | 302,544 | 322,512 |
|
US Treasury and Government [Member]
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Amortized Cost | 112,473 | 168,104 |
| Gross Unrealized Gains | 1,313 | 1,368 |
| Gross Unrealized Losses | (23) | (12) |
| Fair Value | 113,763 | 169,460 |
|
Residential Mortgage Backed Securities [Member]
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Amortized Cost | 181,429 | 148,329 |
| Gross Unrealized Gains | 6,292 | 3,727 |
| Gross Unrealized Losses | 0 | (64) |
| Fair Value | 187,721 | 151,992 |
|
Corporate Securities [Member]
|
||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Amortized Cost | 1,060 | 1,060 |
| Gross Unrealized Gains | 0 | 0 |
| Gross Unrealized Losses | 0 | 0 |
| Fair Value | $ 1,060 | $ 1,060 |