Net Income Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended					1 Months Ended	3 Months Ended		9 Months Ended		1 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 3.375% Convertible Notes [Member]	Sep. 30, 2013 3.375% Convertible Notes [Member]	Sep. 30, 2014 3.375% Convertible Notes [Member]	Sep. 30, 2013 3.375% Convertible Notes [Member]	Sep. 30, 2014 Convertible Debt [Member] 3.375% Convertible Notes [Member]	Jun. 24, 2014 Convertible Debt [Member] 3.375% Convertible Notes [Member]	Jun. 16, 2014 Convertible Debt [Member] 3.375% Convertible Notes [Member]	Feb. 28, 2013 Stock Options [Member]	Sep. 30, 2014 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]	Sep. 30, 2014 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]	Feb. 28, 2013 Restricted Stock Units (RSUs) [Member]	Feb. 28, 2013 Performance Share Awards [Member]	Sep. 30, 2014 Performance Share Awards [Member]	Sep. 30, 2013 Equity Award Modification [Member]
Net Income Per Common Share [Line Items]
Weighted average number of diluted shares outstanding adjustment (in shares)	630,329	1,295,270	1,046,576	1,035,506
Adjustments to net income for purposes of computing income available to common stockholders	$ 0	$ 0	$ 0	$ 0
Antidilutive securities excluded from computation of EPS													92,049	27,300	92,049	177,550
Options, granted (in shares)												86,300
Other than options, granted (in shares)																	93,989	84,654
Award vesting period																			3 years
Minimum range of target award of stock plan																			0.00%
Maximum range of target award of stock plan																			250.00%
Exercise period of stock options from date of grant															10 years
Exercise period of stock options from date of retirement															5 years
Stock compensation expense			5,453	16,092																10,492
Convertible note repurchases, par value											224
Stated interest rate									3.375%
Convertible debt										$ 55,412
Potential shares issuable under net share settlement method (in shares)					0	286,205	326,973	128,594