Investments - Additional Details (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014 security	Dec. 31, 2013 security
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 155,136	$ 106,977
Number of Mortgage-Backed securities with unrealized losses	22	20
Number of Mortgage-backed securities	51	33
Par Value of Mortgage-backed securities pledged to FRB	149,057	103,049
Ginnie Mae
Schedule of Available-for-sale Securities [Line Items]
Number of Mortgage-Backed securities with unrealized losses	11
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	155,136	106,977
Mortgage-backed securities | Ginnie Mae
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	76,274
Mortgage-backed securities | Fannie Mae
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,163
Mortgage-backed securities | Freddie Mac
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 11,699