Investments - Schedule of Available-for-sale Securities Reconciliation (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Available for sale securities:
Amortized Cost	$ 441,562,000	$ 627,462,000
Fair Value	434,587,000	640,212,000
Other investments, at cost	12,605,000	14,294,000
Gross Unrealized Gains, Securities Available for Sale	4,358,000	13,492,000
Gross Unreailzed Losses, Securities Available for Sale	11,333,000	742,000
Percentage of shareholders' equity held by one issuer, maximum	10.00%	10.00%
Available-for-sale securities pledged as collateral, fair value	270,100,000	359,300,000
Mortgage-backed securities, weighted average life	5 years
Obligations of U.S. Government sponsored enterprises
Available for sale securities:
Amortized Cost	93,218,000	149,039,000
Fair Value	93,530,000	152,368,000
Gross Unrealized Gains, Securities Available for Sale	700,000	3,329,000
Gross Unreailzed Losses, Securities Available for Sale	388,000	0
Obligations of states and political subdivisions
Available for sale securities:
Amortized Cost	49,721,000	51,202,000
Fair Value	48,943,000	53,003,000
Gross Unrealized Gains, Securities Available for Sale	983,000	2,279,000
Gross Unreailzed Losses, Securities Available for Sale	1,761,000	478,000
Residential mortgage-backed securities
Available for sale securities:
Amortized Cost	298,623,000	427,221,000
Fair Value	292,114,000	434,841,000
Gross Unrealized Gains, Securities Available for Sale	2,675,000	7,884,000
Gross Unreailzed Losses, Securities Available for Sale	9,184,000	264,000
Des Moines [Member]
Available for sale securities:
Other investments, at cost	6,000,000
San Francisco [Member]
Available for sale securities:
Other investments, at cost	$ 700,000