Fair Value Measurements - Assets and Liabilities Measured at Fair Value, Recurring (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets:
Securities available for sale, at fair value	$ 710,625	$ 705,751
GSE collateralized mortgage obligations
Assets:
Securities available for sale, at fair value	273,417	274,101
GSE mortgage-backed securities
Assets:
Securities available for sale, at fair value	409,809	404,996
Trust preferred securities
Assets:
Securities available for sale, at fair value	4,050	3,697
Municipal bonds
Assets:
Securities available for sale, at fair value	6,118	5,936
Mutual funds
Assets:
Securities available for sale, at fair value	17,231	17,021
Recurring basis \| Estimate of Fair Value \| GSE collateralized mortgage obligations
Assets:
Securities available for sale, at fair value	273,417	274,101
Recurring basis \| Estimate of Fair Value \| GSE mortgage-backed securities
Assets:
Securities available for sale, at fair value	409,809	404,996
Recurring basis \| Estimate of Fair Value \| Trust preferred securities
Assets:
Securities available for sale, at fair value	4,050	3,697
Recurring basis \| Estimate of Fair Value \| Municipal bonds
Assets:
Securities available for sale, at fair value	6,118	5,936
Recurring basis \| Estimate of Fair Value \| Mutual funds
Assets:
Securities available for sale, at fair value	17,231	17,021
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| GSE collateralized mortgage obligations
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| GSE mortgage-backed securities
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Trust preferred securities
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Municipal bonds
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Mutual funds
Assets:
Securities available for sale, at fair value	17,231	17,021
Recurring basis \| Significant Other Observable Inputs (Level 2) \| GSE collateralized mortgage obligations
Assets:
Securities available for sale, at fair value	273,417	274,101
Recurring basis \| Significant Other Observable Inputs (Level 2) \| GSE mortgage-backed securities
Assets:
Securities available for sale, at fair value	409,809	404,996
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Trust preferred securities
Assets:
Securities available for sale, at fair value	4,050	3,697
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Municipal bonds
Assets:
Securities available for sale, at fair value	4,972	4,824
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Mutual funds
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| GSE collateralized mortgage obligations
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| GSE mortgage-backed securities
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Trust preferred securities
Assets:
Securities available for sale, at fair value	0	0
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Municipal bonds
Assets:
Securities available for sale, at fair value	1,146	1,112
Recurring basis \| Significant Unobservable Inputs (Level 3) \| Mutual funds
Assets:
Securities available for sale, at fair value	$ 0	$ 0