Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	$ 310,000
Interest Rate Derivative Assets, at Fair Value	1,948		6,604
Unrealized Gain in Accumulated Other Comprehensive Income	1,184		4,014
Not Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	515,646		588,972
Estimated Fair Value of Interest rate swap	(388)		(374)
Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Term, Lower Maturity Range Date	Jul. 01, 2014
Term, Higher Maturity Range Date	Jul. 01, 2021
Pay Fixed / Receive Variable Swaps [Member] | Not Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	257,823		294,486
Estimated Fair Value of Interest rate swap	13,490		13,296
Pay Variable / Receive Fixed Swaps [Member] | Not Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	257,823		294,486
Estimated Fair Value of Interest rate swap	(13,878)		(13,670)
Interest Rate Swap April 2015 April 2018 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	33,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	1.428%
Term, Lower Maturity Range Date	Apr. 01, 2015	[1]
Term, Higher Maturity Range Date	Apr. 01, 2018	[1]
Interest Rate Derivative Assets, at Fair Value	101		463
Unrealized Gain in Accumulated Other Comprehensive Income	61		281
Interest Rate Swap October 2015 April 2019 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	33,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	1.857%
Term, Lower Maturity Range Date	Oct. 01, 2015	[1]
Term, Higher Maturity Range Date	Apr. 01, 2019	[1]
Interest Rate Derivative Assets, at Fair Value	236		837
Unrealized Gain in Accumulated Other Comprehensive Income	143		509
Interest Rate Swap October 2015 October 2019 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	33,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	1.996%
Term, Lower Maturity Range Date	Oct. 01, 2015	[1]
Term, Higher Maturity Range Date	Oct. 01, 2019	[1]
Interest Rate Derivative Assets, at Fair Value	256		1,007
Unrealized Gain in Accumulated Other Comprehensive Income	156		612
Interest Rate Swap April 2016 April 2020 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	33,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	2.265%
Term, Lower Maturity Range Date	Apr. 01, 2016	[1]
Term, Higher Maturity Range Date	Apr. 01, 2020	[1]
Interest Rate Derivative Assets, at Fair Value	304		1,172
Unrealized Gain in Accumulated Other Comprehensive Income	185		712
Interest Rate Swap April 2016 April 2022 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	34,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	2.646%
Term, Lower Maturity Range Date	Apr. 01, 2016	[1]
Term, Higher Maturity Range Date	Apr. 01, 2022	[1]
Interest Rate Derivative Assets, at Fair Value	353		1,818
Unrealized Gain in Accumulated Other Comprehensive Income	215		1,105
Interest Rate Swap October 2016 October 2020 [Member] | Designated as Hedging Instrument [Member]
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	34,000
Variable Interest Rate	3 month LIBOR
Fixed Interest Rate	2.523%
Term, Lower Maturity Range Date	Oct. 01, 2016	[1]
Term, Higher Maturity Range Date	Oct. 01, 2020	[1]
Interest Rate Derivative Assets, at Fair Value	316		1,307
Unrealized Gain in Accumulated Other Comprehensive Income	192		795
Interest Rate Swap July 2014 July 2021 [Member] | Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	27,500
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	27,500
Variable Interest Rate	1 month LIBOR
Fixed Interest Rate	2.09%
Interest Rate Derivative Assets, at Fair Value	151		0
Unrealized Gain in Accumulated Other Comprehensive Income	92		0
Interest Rate Swap July 2014 July 2022 [Member] | Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	27,500
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	27,500
Variable Interest Rate	1 month LIBOR
Fixed Interest Rate	2.27%
Term, Lower Maturity Range Date	Jul. 01, 2014
Term, Higher Maturity Range Date	Jul. 01, 2022
Interest Rate Derivative Assets, at Fair Value	86		0
Unrealized Gain in Accumulated Other Comprehensive Income	52		0
Interest Rate Swap July 2014 July 2023 [Member] | Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	27,500
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	27,500
Variable Interest Rate	1 month LIBOR
Fixed Interest Rate	2.42%
Term, Lower Maturity Range Date	Jul. 01, 2014
Term, Higher Maturity Range Date	Jul. 01, 2023
Interest Rate Derivative Assets, at Fair Value	114		0
Unrealized Gain in Accumulated Other Comprehensive Income	69		0
Interest Rate Swap July 2014 July 2024 [Member] | Designated as Hedging Instrument [Member]
Interest rate swap agreements [Abstract]
Notional Amount of Interest rate swap	27,500
Forward Cash Flow Hedge Relationship [Abstract]
Forecasted Notional Amount	27,500
Variable Interest Rate	1 month LIBOR
Fixed Interest Rate	2.50%
Interest Rate Derivative Assets, at Fair Value	31		0
Unrealized Gain in Accumulated Other Comprehensive Income	$ 19		$ 0

[1] No cash will be exchanged prior to the term.