Fair Value - Fair Value Measurements for Items Measured at Fair Value (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale		$ 15,332	$ 23,998
Other real estate owned		9,949	7,039
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	[1]		1,459
Other real estate owned	[2]		6,441
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	[3]	950,503	790,766
Loans held for sale	[4]	15,332	23,998
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	[3]	100	225
Loans held for sale	[4]	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	[3]	950,403	790,541
Loans held for sale	[4]	15,332	23,998
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	[3]	0	0
Loans held for sale	[4]	0	0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	[1]	4,120	7,511
Other real estate owned	[2]	9,949	7,039
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	[1]	0	0
Other real estate owned	[2]	0	0
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	[1]	3,170	6,052
Other real estate owned	[2]	0	$ 598
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	[1]	950
Other real estate owned	[2]	$ 9,949

[1] See Note F. Nonrecurring fair value adjustments to loans identified as impaired reflect full or partial write-downs that are based on the loan’s observable market price or current appraised value of the collateral in accordance with ASC 310.

[2] Fair value is measured on a nonrecurring basis in accordance with ASC 360.

[3] See Note D for further detail of fair value of individual investment categories.

[4] Recurring fair value basis determined using observable market data.